You said you feel like your bass is anemic - have you done room measurements or tried different sub positions? It's possible that your main listening position is in a null and if that's the case bigger, badder subs aren't going to help you. If you've already done that and your pushing your current subs to the limit, I'd recommend Power Sound Audio. 15"' are probably at the top of your budget, but if you could swing a pair of 18's that would be a huge upgrade. There's no substitute for cone surface area.
If you would be open to DIY, the VBSS is a great musical DIY sub with tons of mid-bass. You could build a pair and buy an amp for around $600.
7.4.4 Theater Room: JVC-RS500, Silver Ticket AT 2.35:1 142”, Onkyo RZ830, Anthem PVA-7, Panasonic UB420, Apple TV 4K, JBL Studio 530’s, Dual Driver VBSS
3.1 Living Room: Samsung 64” F8500 Plasma, Anthem MRX 300, Dynaudio Audience 52’s, Dynaudio Audience 122C, NHT SubOne, Roku Express (2019)