Buying a first-round draft AX router right now with the intent of "future proofing" is not a wise move.I've been looking at 8 port with 802.3ad routers for a while but decided to hold off for a little while, then the AX88U was announced and considering it's spec and the fact it was about as future proof as it is possible to get it seemed like the right choice to replace an older TP-Link router.
You'll be paying a premium price and buying a product with features (11ax support) you are unlikely to be able to take advantage of for a few years. By then, prices will have dropped, the technology will have stabilized and the next generation of routers will be hitting the market.
Why are you looking for an 8 port router with port aggregation anyway, when an 8 port gigabit smart switch is $60 and can be added to any router?