Connect 2.4 and 5GHz in bridge

I have ac2 like gw in my house and another ac2 as a client in my desk (for pc).
I tunned my connections via 2.4GHz and 5Ghz, 5GHz via nv2 has the best throughput but with random lags, 2.4GHz is mor stable but with 60-70Mb/s in max.
I have an idea make load balancer from 2.4 and 5GHz like I made several times in customers gw (ih the have 2 net connections). But I have no idea where I should begin. Should I make bonding interface with wlan1,2 in the both side with 802.3ad? But 2.4Hz ap si multipoint, 5Ghz is ap only for my ac2 klient....is there any problem with these settings? Or whats the best scenario?
Edit: I`ve tried bonded the both sides but there is a broken connection then.
If Ive bonded only one side (AP) connection is working but only via one vlan.

Get a drill and wire ethernet,
Up into the attic and back down or through closets etc…
Your best bet will be 2gig between the units 5ghz to share locally.
Anything else is sub optimal.
in fact I would buy the wireless wire 60hz and connect from lower floor to upper floor instead of what you are doing.
Or powerline

This is my home networok, mate.
I dont need the maximum speed up to Gb/s (I have only 50Mb net connection). But Id like to get better speed because sometimes I make big-data moving and my NAS is in the rack, so I`m connected only via wifi to the rack.
My idea is using the both wifi connection based on bonding direction.

Sharing same radio for both uplink and client connections is bad to begin with.

Bonding works fine if both (all) member links are of approximately same speed, work reliably, without delay spikes. And most importantly: almost all transmit algorithms will use same link for all packets belonging to same connection (e.g. TCP connection between SMB client and server). Notable exception is balance_rr, which is not part of 802.3ad specification, it’s linux extension (do it should work fine between a pair of mikrotiks). However, ballance_rr can not guarantee in-order packet delivery and TCP stacks sometimes don’t like it (athough TCP should be able to handle it). If connection is UDP (e.g. NFS over UDP), things are even worse because application should be able to handle out-of-order drlivery and quite many applications can’t.

WiFi is simply not fit for masive throughputs in non-ideal conditions.