Best bathtub for a big baby?

Jessa

My LO is 15 weeks old, about 16 pounds and 26” long. He’s outgrown his baby bathtub but he can’t support himself enough to be in the actual tub (even with my help, of course). Was looking into the shnuggle but I think he would outgrow that quickly. Does anyone have recommendations? I bath him by myself so I really need a tub or something supportive for him. Thanks!