How to increase task priority

Well, there's always the command line utility "renice", which will re-prioritize running processes.

But that's a low-level BSD Unix utility and the macOS kernel scheduler is actually quite sophisticated...so maybe a better question is what task do you think is lacking in priority or resources and why? e.g., there's no use running renice or otherwise adjusting priority on a process that is bound by unresolvable constraints like I/O limitations or your memory pressure being too high.

Also, if you are actually running 15.2, there are fairly strict limitations as to what can be discussed due to the Beta testing Terms of Use

renice, as mentioned by g_wolfman

You can do the opposite, and slow down other resource hogs, to allow more resources for your preferred app. St Clair Software’s App Tamer could do that for you in a GUI manor.