Max inventory on catalysts

Bigrig3

So long story short I want to upgrade my 4* strange but I need 3 T4 catalysts. I have a total of 4 but my guess is since I’m lvl 17 I can only hold a max of 2 T4 catalysts in my inventory and I have 2 in my stash. I have 10 days before they de spawn so if y’all could help me with what lvl I gotta grind to get to a max inventory of 3 it would help tremendously. Thank y’all in advance!