Pretty much the only thing that I would hate about Ronaldo gone is if we panic buy some older experienced name as his replacement that we'll have a hard time getting rid of next couple of seasons.
If the club likes the potential in Vlahovic and sees him as ideal 9 then sure, go all in, fix a deal with Fio with 3 days remaining of the mercato window, he fits the rejuvenation plan perfectly. If it's someone else in his early 20s, then go ahead, try your best.
If serious targets are off limits so close to deadline then don't just buy a random player for the sake of it, call it a day and negotiate next window/summer.
We have a fine squad as it is, a top class manager won't have a problem to build a working machine from it, then next summer spend big on generational talents, De Ligt was awesome, Chiesa was awesome, Locatelli was awesome, just keep it up with smart investments and keep your younger key players in the squad and the new winning cycle would be set.