Performance is pretty bad for my ROG ally Z1.

I use an ROG ally to play my games, and I normally like to play Sonic Generations, I can play it at 1080p, high settings, and with antialiasing at 60fps on the chemical plant act 2(the laggiest level) while my power mode is set at 15watts.

So when I saw the port, I was exited to finally play Sonic Unleashed, while I did expect the performance to be a bit worse than generations, I didn't really expect it to be this bad, because they both are in the same engine, and I have played the Unleashed Project on Sonic Generations, which was a bit worse than normal generations but generally reaching 60fps most of the time.

To play Sonic Unleashed I have to set the game 1080p/90% resolution scale, low shadows, antialiasing off, while playing windmill isle act 2 (which is not very demanding for the most part) and power mode set to 20watts to barely reach a kind of consistent 60fps.

Is this an issue of the game just being less optimized because of it being made in an older version of the engine? or is an issue of it being a port? if it is because of it being a port, will it get better? and if it is the other option, are there ways to optimize the game further?

I tried not to sound like a little kid complaining their PC is not powerful enough, that is why I compared it to Sonic Generations and the Unleashed Project mod.

I tried looking for this online but it just seems nobody plays this game on an ROG Ally.

Edit: I just checked Steam Deck performance... why is the only way to get a consistent 60fps is by playing at 720p? That is worst than what I thought.

Reproduce Sonic Unleashed performance on the ROG Ally Z1 and Steam Deck using the reported 1080p settings, power modes, and Windmill Isle Act 2 scenario. Compare the results with Sonic Generations and determine whether a specific optimization target or reproducible regression can be identified; done requires a confirmed cause or actionable performance finding.