The newest 10.2.4-1.0-00024 firmware at Codeaurora (https://source.codeaurora.org/quic/qsdk/oss/firmware/ath10k-firmware/plain/ath10k/QCA988X/hw2.0/) seems to have mesh support. I have it running now on my Archer C7v2 (I am not using mesh though), and it works very well. Signal seems stronger too, and I don't have to use "disassoc_low_ack = 0" anymore to prevent the "disconnected due to excessive missing acks" anymore.
Dmesg reports: [ 16.536646] ath10k_pci 0000:01:00.0: firmware ver 10.2.4-1.0-00024 api 5 features no-p2p,raw-mode,mfp,allows-mesh-bcast crc32 2a48e27d
Excellent so far. I did not have a single disconnect or other problems. Especially no "disconnected due to excessive missing ACKs" messages I used to have with older firmware versions.
Firmware 10.2.4.1.0-00029 is now default in the git repo, but is has major issues for me. Especially with streaming (like youtube, but also rdp sessions over the internet), disconnects occur very frequently. Best firmware so far for me is 10.2.4.1.0-00025 from Codeaurora.