Put the 5* down… If you’re short of compasses, I can almost guarantee you don’t have the AM’s necessary to max them - a maxed 4* in almost all cases will help you more than a 3.70 5*.
Before suggesting who to ascend to tier 4 (ie: 4*), what do you have maxed already?
What else do you have in the works for 4*?
LiXiu is an underrated defence tank and useful in farming maps… Not the hardest hitter, but sturdy and a delaying tactic.
Gadeirus is a great support hero, he’s toothless even maxed but useful support for those either side of him, he’s probably lowest priority.
Scarlett is a glass cannon… Hits great, dies easy… She won’t be much fun until maxed, depending on what you need, there’s a case to be made for her.
Wu is great for titans, events… Anything where you’re prepared to gamble to punch above your weight - on average you’ll do much better with him than without him, but when the gamble goes against you it feels like it’s really against you.
Boril… I just don’t rate. He’s sturdy as heck and riposte is effective against newbs who either don’t have or don’t understand the importance of dispellers… But beyond a certain point, you’ll never touch him again.
If you have other 4* , consider parking him permanently and work on a more useful card - Li is almost as good a tank and you’ll find use for her further into the game (especially if you have her costume).
This is just a really general summary…
What else do you have?
What do you have maxed?