What do I need to achieve link aggregation in openwrt? TP-Link Archer C50 v4
The switch chip internally connected to cpu with 1gbps link, but eth ports are 100mbit. I need 200mbit throughput, so I think to bond 2 ports in one into "1000baseT" link with expected speeds of 200mbit. I need it for wifi 5ghz
On the otherside I have Mikrotik CRS210 with bonding prepared
very few targets have hardware offloading bonding/ LAGG support (I'm not aware of any)
there is also the performance of the CPU for the internal switch to consider
only very powerful targets (x86_64) have the raw performance to profit from software based bonding
mt7628 with only 100BASE-T ports certainly does not
The sensible solution would be to buy a (second hand?) router with
native 1000BASE-T (or 2.5GBASE-T) ports
and the performance to actually route at those speeds (e.g. filogic, maaaybe ipq807x/ ipq60xx/ ipq50xx (if you don't need to go quite the full 1000 MBit/s); x86_64 is always an option for top performance)
You are asking too much from this very-low end device, while much better (1000BASE-T ports, even if the routing performance couldn't quite fill that out) was the norm ~15 years ago already.
This also/ already applies to 'just' AP usage, as the 5 GHz radio in your router is ~3 times faster than the ethernet side you need as wired backhaul to your router. This device is just mis-designed from the factory, coupling a 802.11ac radio with 100 MBit/s ethernet ports only (it might have been excusable for 802.11n, but not for 802.11ac).
There's funny story behind my tplink trash. I bought it in 2019 to replace my malfunctioning ADSL router provided by ISP. After it arrived, I realized WAN port is not rj11, thus not compatible. Back then I didnt know anything about networking.
Then I used onpar with Huawei ONT as wifi ap, cuz huawei got only 2.4ghz wifi and i have 100mbit up/down fiber.
Then I flashed openwrt, to find out it has only 8mb flash making it practically useless for anything serious.
Now I got Mikrotik CRS210, just to realize it doesnt have VLAN filtering hardware offload (but CPU might be enough for 1gbps).