I like Freerider to warm up with, especially if I haven't flown for a while, (plus the computer load is a lot less) but Liftoff feels much more real to me.
My computer can't handle the high graphic settings either without affecting everything else (especially in Liftoff) so I just lower it to the point where the
flow remains smooth and still enjoy it...Real life damage levels get annoying so I'll often use "God Mode" (especially when hitting gates) just to keep flying
even though clipping that last gate would've wasted my props ... lol ... After it starts feeling really good to you then you can turn off God mode, turn on video
flicker/interference, and all the other aspects that make it even more realistic (but annoying).
Do look around in the game's chat area too because there's a lot of talk and help in there about different aspects of the game, PIDs and tuning, etc.
Haven't tried Velocidrone yet, but tried DRL and found it basically unusable.
Don't forget in the radio's settings to
turn off the transmitter section when using it for SIMs, there's no point in generating RF power for nothing.
I found it's also beneficial with tweaking the SIMs to have each one setup as a different model in the radio. That way subtle combinations of settings in the radio combine
with settings in the SIM for a more refined control of the experience.
Once you get everything dialed in just right it IS almost like flying for real, except it's free to crash and you don't even have to run over and pick it up, batteries can last forever,
and like you mentioned, you get to try out different quads, motor/prop combos, etc, etc.