Yamcha vs Dragon Ball Z/Super

How far does he get in each round?

Round 1: Super Saiyan
Round 2: Super Saiyan 2
Round 3: Super Saiyan 3
Round 4: Super Saiyan Blue (normal boost, no ritual crap)
Round 5: Ultra Instinct Mastered

Yamcha arguably gave up by the time the Cell Arc rolled around. He is seriously lucky to get past Imperfect Cell with SSJ3.

Super Saiyan Blue's stamina drain fucks him over before he can do anything.

Ultra Instinct Mastered he lasts a single second before reverting to base.

Round 1 - Shouldn't get past 100% Frieza, imo.

Round 2 - Beats Yardrat SSJ Goku, but that's about it.

Round 3 - He should be strong enough to beat Android 16. Though Semi-Perfect Cell beats him handily.

Round 4 - I don't really have SSJB that big of a boost, it's just a bit over SSJ3's one. It is compensated by the fact that Goku/Vegeta got too strong in base. Anyways, if he can hold the form perfectly, He could beat Semi Perfect Cell.

If he got the ritual, he'd be able to solo Z and GT.

Round 5 - MUI is more than 20 times SSJB. I have UI around 40 times SSJB, and MUI is around 1.2x stronger than it, so around MUI is around 48 times SSJB.
With this kind of boost, he can easily take on an SSJ3 tier opponent(Kid Buu, SSJ3 Goku...).