De-rusting, it's something I'm well acquainted with.
You'll have less stamina, speed, dexterity, movements feel more stiff, acc is worse, etc. All that to say, don't expect to get straight into what you used to play. You gotta build it back up, which doesn't take long.
Give it a few weeks, or 1-2months and you'll be equal or fairly close to where you used to be.
I spent alot more time playing easier maps with the occasional harder map. when I was getting back into the groove of things. My physical conditioning was poor, so I couldn't handle multiple harder songs without fumbling on everything. After some time it became less and less of a problem, till I eventually got back into what I used to play and surpassed old me before I shortly stopped playing again.
More important than anything else is to not rush progress have fun with it.