Can't decide what to buy.

So I'm sitting on like 2.2k IP and considering buying either spell vamp quints for mundo or possibly tahm or ekko (eventually).

Ekko has kind of moved away from tanky utility builds toward more AP damage builds if I understand his current balance right. I really like tanky champs, usually more utility, but damage and brawling is nice too (thus liking mundo and stuff like maokai who does good damage early in lane), so I probably will end up not getting Ekko if I'm right about his balance (need to try out on free week more).

Tahm looks really interesting and kind of similar (but better) to shen. Big shield, two forms of CC (stun and devour), decent sustain, decent damage. I feel like he may be a little over tuned numbers wise though right now and is likely to get some incoming nerfs in the next few patches so I'm hesitant to pick something up for so much IP that I may end up only being interested in now bc it is a bit over tuned and won't want to play him when he's more balanced.

Any advice/thoughts on if I'm right or wrong on my understanding of Ekko/Tahm?