I have looked up a few pages of suggestions and haven't seen a write up about this, so I might as well do this as I have the funny avatar with the sonic homage character in The Hex.
Photon Dash and Glide. Climbing up walls. Swimming. We got it all. It is literally screaming for this. Give us running content! And you are the Sonic publisher? C'mon! Do it! (Please)
Not just that, we got our Halpha and our Cocoons and those Towers... we can have all of that!
1 - The overworld competitions!
How about, each day, or every few hours or so, we got some nice ARKS Training and those leg muscles and photons flowing? You could have some random algorythm make paths through some of the beautiful and full of cliffs promenades in West Aelio, through waterfalls and caves in South Aelio... gather up and just run and climb and fly on a set limited by some markers that add time and/or disqualify if going not over there. No weapons being able to be used either, of course.
You could also get dangerous and make us go through combat zones and dodge enemies. Or plant them in the tracks. Or or or make us go through a Gigantix in the middle of a storm.
No need for big prices, some racing gear or even grinders and a bit of meseta if feeling stingy. Or some Sonic related stuff!
Why do I not suggest just having a track able to be timed attacked whenever? Because bots.
2 - The coccoon competitions!
Similarly to idea 1 but this time, it is VR generated tracks. Being VR based allows for more fantastical level design and verticality. In short, they could be similar to Timed Attack stages in regular PSO2 but without the fighting.
You already have track based tests in some Cocoons, so it is just expanding on that idea and making it announced like UQs when they are going to start. They would be able to be accessed from some new Cocoon focused on that. Maybe a built one set in our Town copying the tech for training purposes.
3 - Cocoon stages and challenges, expanded.
You most likely have plans to add more of those platforming challenges in the future on other regions but... why not have a full on VR mode that has all that and allows us to race each other at our heart's content? You could have a great variety of those! I am not sure if SEGA checks the KR market, but there was this reeeeeally old f2p MMO called Tales Runner that was aaaaall about platforming based and sports fantasy based racing.
Some good old challenge board similar to the old Matter Board like if you selected clicking the panel to get to them and give some cute rewards showing off your platforming skills would be neat!
Really hoping we can get these great new movement skills to use on something like this!