Replacement for linksys wrt 1900acs

I am currently having a Linksys wrt 1900acs. I am running openwrt, samba server and minidlna. And i must sat IT is running VERY smooth.
I am looking for a replacement because the router is 64mb flash Storage and is VERY close to run out for Space.
I bought a Linksys mr9600, my plan was to install openwrt when IT was available, and use the stock firmware. But linksys has removed the dlna feature, so I will return it.
But what should I go for instead? I am looking at the netgear nighthawk rax50. Openwrt isn’t available for the router yet, but I will use stock firmware until it is available.
I am prioritizing fast and long range wifi very high.
Are there any other routers I should consider buying?

Buy some cheap x86, repurpose the 1900 as AP.

Read Tips for getting cheap used x86-based firewall with full Gbit NAT (a PC Engines APU) if you are in the US