Lucas chess?
SCID vs SCID vs PC

Good luck with that, sound interesting! Unfortunately I can't help you much because I am still somewhat new to chess, too.

Lucas chess?
Lucas chess let's you keep a database of your own games, with search capabilities? (There's a whole lot about that software package I don't know!)

Chess.com has it's own SCID equivalent, albeit well hidden. Try Learn --> Explorer --> Select 'My Games' rather than 'Master Games'. There is also a more selective Library|Collections system. The number of games you can store is 100K if a Gold member. Not saying this system is better than SCID but it is there to use. However, the analysis features are likely to be better. When I play a particularly good game I normally add it a Library collection as most of my games after analysis are not worth looking at twice!
Thanks for the response, Charlie.
What I'm most interested in is a combination of the "slow" games I play here (30+ minutes, bu tnot daily) *and* the games I play at OTB tournaments. (The games I play in OTB tourneys I put into my Libraries here) I'm guessing (tell me if I'm wrong) that "Explorer | My Games" will not include those games.
I'm also looking for decent search/filter capabilities. I.e., this opening that I screwed up today, I think I've played it before, where/when? I don't think I can search my OTB games in my library for that, can I?

Chess.com has it's own SCID equivalent, albeit well hidden. Try Learn --> Explorer --> Select 'My Games' rather than 'Master Games'. There is also a more selective Library|Collections system. The number of games you can store is 100K if a Gold member. Not saying this system is better than SCID but it is there to use. However, the analysis features are likely to be better. When I play a particularly good game I normally add it a Library collection as most of my games after analysis are not worth looking at twice!
Thanks for the response, Charlie.
What I'm most interested in is a combination of the "slow" games I play here (30+ minutes, bu tnot daily) *and* the games I play at OTB tournaments. (The games I play in OTB tourneys I put into my Libraries here) I'm guessing (tell me if I'm wrong) that "Explorer | My Games" will not include those games.
I'm also looking for decent search/filter capabilities. I.e., this opening that I screwed up today, I think I've played it before, where/when? I don't think I can search my OTB games in my library for that, can I?
Try to put the position in the explorer? That could clarify some things.

Chess.com has it's own SCID equivalent, albeit well hidden. Try Learn --> Explorer --> Select 'My Games' rather than 'Master Games'. There is also a more selective Library|Collections system. The number of games you can store is 100K if a Gold member. Not saying this system is better than SCID but it is there to use. However, the analysis features are likely to be better. When I play a particularly good game I normally add it a Library collection as most of my games after analysis are not worth looking at twice!
Thanks for the response, Charlie.
What I'm most interested in is a combination of the "slow" games I play here (30+ minutes, bu tnot daily) *and* the games I play at OTB tournaments. (The games I play in OTB tourneys I put into my Libraries here) I'm guessing (tell me if I'm wrong) that "Explorer | My Games" will not include those games.
I'm also looking for decent search/filter capabilities. I.e., this opening that I screwed up today, I think I've played it before, where/when? I don't think I can search my OTB games in my library for that, can I?
yeah, how is it supposed to know those are your otb games?

Charlie -- thanks for your lengthy responses. We have some similarities.
First off, I have PNG Chessbook -- might that be what you're referring to? It also has Stockfish 8, and I like it because it's a standalone; i.e., it doesn't need a network connection. In fact, what I do is enter my games there, and then I copy the png into chess.com and put them into libraries.
I have separate libraries for my OTB games, and games that are 30 minutes or longer (because, and you noted, fast games can often be blunderfests).
I analyize my games in chess.com, and I'm fine there.
But what I'm really looking for is a searchable database, that can answer questions such as (a) I have played against so-and-so before? Or (b) did I play French-Exchange before? What did I do then? Or (c) I want to see that game where I faced the KID the first time, in July, and see what I did then. And I want to be selective about which games go in there (as I mentioned before: exclude anything fast, exclude daily games, etc.). Can SCID do those things? Do you know anything about SCID v PC?
FWIW, I hear you about openings. I think tons of people make (including me) make that same mistake. But why, really, do we lose games (those of us in the under 1600 crowd)? Just go back and look at your last 10 losses. Was it a bad opening? Bad pawn structure? Bad endgame? No, 90% of the time (renown chess instructor Dan Heisman says is 99% of the time, in a game with two players U1600) it's because we allowed a tactic, or failed to see a tactic that we could have played.
(Dan Heisman's theory about those U1600 learning openings: take each game we play -- including rapid -- and determine: what's the first non-book (or bad) move that I made. Then just add that *one* move to your repertoire/memory so that if you face that exact situation again, you won't make the same mistake).
EDIT/UPDATE: Just found this: https://www.chess.com/blog/SamCopeland/tutorials---scid-for-the-chess-student
So, I'm finally ready to start making a database of my own games (I'm a bit new to chess software).
I'm trying to figure out the difference between Scid and Scid vs PC. (I'm aware that one began as a fork of the other, but I'm looking for present-day-2021 info)
Any words of wisdom here?
(And I'm open to other alternatives, too!)