To date, only models with WIFI-6: AX, USB-3 and gigabit ports are to be considered as interesting and if possible at a reasonable price
I looked at the characteristics of the Mr8300 that in France you can find 79.99 euros at amazon which seems to correspond
...to you.
Other users with other usecases may find USB3 completely uninteresting, dito for Gigabit and Wifi6.
Apart from that, I wouldn't call 80€ cheap.
Netgear R6700v2 (/6800)
Can get from $20-$50, Mediatek chipset handles a lot in hardware. CPU doesn't break a sweat when this device NATs at a gigabit. MIPS 880mhz cpu is less beefy than ARM devices, but it handles data so well that basically all the CPU power is available for your tasks. This device sold me on Mediatek.
I have two Netgear 6700v2's running as dumb ap's on opposite ends of my home gigabit-wired at the center to my TP-Link Archer A7v5. Each cost ~$40usd all running Openwrt 21.02.1. For wifi-5ghz, I average ~600Mbp/s on the 6700v2 and ~300Mbp/s on the Archer A7v5.
I really dont want the A7v5 and and rather use one of the 6700v2's as my primary, but I cant configure VLANS (vlan filtering) without soft-bricking. Seems the MT6721 chipset on this router use DSA configuration and dont support the older style switch configurations. so its been a dead-end getting vlan tagging working with them. As dumb AP's, they work with multiple vlans, no problem, no config required.
https://github.com/openwrt/openwrt/commit/43f0e386d4e79e9014e926d1d9b5e2ff8f1379cb is available within EU for about 90 EUR over at banggood.com 
ZBTLINK Z100 AX v01 ( WIFI 6 / AX )
You can find at aliexpress for some 57,67 €
Product is with 3 * LAN + 1 WAN gigabits
Mediatek MT7621 - MT 7915e - MT7905D MT7975D
USB-3
WIFI AX
Serial port
Flash 16M Winbond + 256 M ram
Power 12 volts < 1 A
Interestingly, I followed your advice to get a DIR-860L, I may follow this as well, looks like it it quite capable for the money.
Cheers!
A friend of mine got one, seems to run stable in general and range is certainly better.
I've ordered two myself to compare the Linksys MR8300 ones I have. I think they're mainly interesting because ARM64 is a much better platform (including crypto extensions), SoC development seems to be progressing more than IPQ4*** (which works nice although there are some issues with the ethernet related subsystem) and WAVE 2 11ac should be fine too. The DIR-860L isn't bad (MT7621) but its starting to show its age and interest is declining so I would expect more issues further down the road.
Ok, ordered one 870 SEK.
I see it's 280 euros now so definitely NOT a cheap device
Yes, it was on sale briefly.
Gave it a spin today, the included PSU feels really cheap (fire hazard-ish level) so I replaced that another one but other than that it's seems to perform really well. Compared to Linksys MR8300 it seems to have much better performance. I have two connected via WDS between two floors and the Totolink performs about 3 times better than the MR8300 downstairs (~95mbit vs ~270mbit). Hardware crypto also seems to be working although I'm not sure if that also includes the official snapshot images (GCC documentation is a bit unclear about what it enables by default by setting -mcpu=cortex-a53) since I compiled my own image (OpenSSL with all optimization enabled, -O2 instead of -Os for global optimization and lastly enforcing hardware crypto extentions, -march=armv8-a+crc+simd+crypto -mcpu=cortex-a53+crypto vs -mcpu=cortex-a53). Seems to have a very good bang for the buck ratio! =)
Firmware/Image based on commit: https://github.com/openwrt/openwrt/commit/dc2da6a23369c8da069321dcfd593a9cf8c993c6
The cheapest I could find is 280$
Not exactly a bargain 
Maybe soon some comparable device coming out that is a bit more affordable
Also at 90$ i would theoretically have to pay 25$ to 30$ or so on taxes and fees. Theoretically, you never know...
For now Im equipped with two ipq4018 and for the experimental part of my soul a mi ax3600.
Would love to get my hands on an mtk7622, and the two 5GHz radios also sound great...
Infos sur la boutique
Raison sociale : Guangzhou jiachun maoyi youxiangongsi
@anon69880279 did you ever order from them? Seems it's a Chinese seller with warehouse in CZ.
So in the other thread it turned out it's a different type of router? Is it supported by openwrt?
It says "Routeur sans fil A8000RU" so that would be the same as the one I linked
@anon69880279
Historically first gen hardware have always buggy/dodgy so I'd rather go for Wave 2 11ac instead.
Since I am no kernel pro, I may be reading this wrong, but
seems to indicate no dsa support available, but:
https://lwn.net/Articles/883059/
may suggest there is support for it.
I dont know... maybe?
Is the WAN port 2.5Gbps but just not specified in the specs?