Not only would your FIDE rating be lower a few hundred points, but the quality of games would be much better. It's like asking what would the rating the McDonald's food you order be compared to going to a restaurant.
If you are just looking for sustenance and the pat on the back that you play chess (online, during covid, taking your master's lessons in mind, etc...) then you can pretend you are going to get somewhere by online chess.
It's a fruitless question, packed with too many irrelevant variables. What you should do is find people with FIDE ratings, play them and see how you perform. Learn from the mistakes you made.
I've been wondering for a while what my FIDE rating or USCF rating compared to my chess.com rating would be. I know they're probably incomparable, but does anyone have a rough estimate? My chess.com rapid rating is 1700, so what would my actual rating be? I was supposed to go to nationals this past April to get rated, but it was cancelled because of coronavirus. If you have an answer for my question, plz post it below or message me @colorfucake! Thanks!