@hnyman I've been testing Hauke's mac80211-5.6 on ipq806x/ nbg6817 (2*qca9984) and ipq40xx/ map-ac2200 (2*ipq4019+qca9888) with mainline ath10k for almost a day now, which seems to fix the SWBA overrun (FS#2480) so far.
[ 23.552657] Loading modules backported from Linux version v5.7-rc2-0-gae83d0b416db
[ 23.553644] Backport generated by backports.git v5.7-rc2-1-0-gc0c7d2bb
ipq8065/ nbg6817:
[ 23.664944] ath10k_pci 0000:01:00.0: assign IRQ: got 35
[ 23.665337] ath10k_pci 0000:01:00.0: enabling device (0140 -> 0142)
[ 23.665418] ath10k_pci 0000:01:00.0: enabling bus mastering
[ 23.665988] ath10k_pci 0000:01:00.0: pci irq msi oper_irq_mode 2 irq_mode 0 reset_mode 0
[ 36.364777] ath10k_pci 0000:01:00.0: qca9984/qca9994 hw1.0 target 0x01000000 chip_id 0x00000000 sub 168c:cafe
[ 36.364824] ath10k_pci 0000:01:00.0: kconfig debug 0 debugfs 1 tracing 0 dfs 1 testmode 1
[ 36.377088] ath10k_pci 0000:01:00.0: firmware ver 10.4-3.10-00047 api 5 features no-p2p,mfp,peer-flow-ctrl,btcoex-param,allows-mesh-bcast,no-ps crc32 19ca6df2
[ 38.659436] ath10k_pci 0000:01:00.0: board_file api 2 bmi_id 0:1 crc32 85498734
[ 42.422100] ath10k_pci 0000:01:00.0: htt-ver 2.2 wmi-op 6 htt-op 4 cal pre-cal-file max-sta 512 raw 0 hwcrypto 1
[ 42.486143] ath: EEPROM regdomain sanitized
[ 42.486157] ath: EEPROM regdomain: 0x64
[ 42.486169] ath: EEPROM indicates we should expect a direct regpair map
[ 42.486194] ath: Country alpha2 being used: 00
[ 42.486204] ath: Regpair used: 0x64
[ 42.492418] ath10k_pci 0001:01:00.0: assign IRQ: got 37
[ 42.493006] ath10k_pci 0001:01:00.0: enabling device (0140 -> 0142)
[ 42.493104] ath10k_pci 0001:01:00.0: enabling bus mastering
[ 42.493734] ath10k_pci 0001:01:00.0: pci irq msi oper_irq_mode 2 irq_mode 0 reset_mode 0
[ 42.791992] ath10k_pci 0001:01:00.0: qca9984/qca9994 hw1.0 target 0x01000000 chip_id 0x00000000 sub 168c:cafe
[ 42.792048] ath10k_pci 0001:01:00.0: kconfig debug 0 debugfs 1 tracing 0 dfs 1 testmode 1
[ 42.803254] ath10k_pci 0001:01:00.0: firmware ver 10.4-3.10-00047 api 5 features no-p2p,mfp,peer-flow-ctrl,btcoex-param,allows-mesh-bcast,no-ps crc32 19ca6df2
[ 45.134338] ath10k_pci 0001:01:00.0: board_file api 2 bmi_id 0:2 crc32 85498734
[ 48.982782] ath10k_pci 0001:01:00.0: htt-ver 2.2 wmi-op 6 htt-op 4 cal pre-cal-file max-sta 512 raw 0 hwcrypto 1
[ 49.046560] ath: EEPROM regdomain sanitized
[ 49.046578] ath: EEPROM regdomain: 0x64
[ 49.046687] ath: EEPROM indicates we should expect a direct regpair map
[ 49.046714] ath: Country alpha2 being used: 00
[ 49.046725] ath: Regpair used: 0x64
ipq4019/ map-ac2200:
[ 21.906310] ath10k_pci 0000:01:00.0: enabling device (0140 -> 0142)
[ 21.907034] ath10k_pci 0000:01:00.0: pci irq msi oper_irq_mode 2 irq_mode 0 reset_mode 0
[ 22.553060] ath10k_pci 0000:01:00.0: qca9888 hw2.0 target 0x01000000 chip_id 0x00000000 sub 0000:0000
[ 22.553108] ath10k_pci 0000:01:00.0: kconfig debug 0 debugfs 1 tracing 0 dfs 1 testmode 1
[ 22.565537] ath10k_pci 0000:01:00.0: firmware ver 10.4-3.9.0.2-00054 api 5 features no-p2p,mfp,peer-flow-ctrl,allows-mesh-bcast,no-ps crc32 68d870ac
[ 22.917507] ath10k_pci 0000:01:00.0: board_file api 2 bmi_id 0:17 crc32 f228337a
[ 24.822196] ath10k_pci 0000:01:00.0: htt-ver 2.2 wmi-op 6 htt-op 4 cal pre-cal-file max-sta 512 raw 0 hwcrypto 1
[ 24.934902] ath: EEPROM regdomain sanitized
[ 24.935001] ath: EEPROM regdomain: 0x64
[ 24.935051] ath: EEPROM indicates we should expect a direct regpair map
[ 24.935187] ath: Country alpha2 being used: 00
[ 24.935240] ath: Regpair used: 0x64
[ 25.918886] ath10k_ahb a000000.wifi: qca4019 hw1.0 target 0x01000000 chip_id 0x003b00ff sub 0000:0000
[ 25.918932] ath10k_ahb a000000.wifi: kconfig debug 0 debugfs 1 tracing 0 dfs 1 testmode 1
[ 25.930761] ath10k_ahb a000000.wifi: firmware ver 10.4-3.6-00140 api 5 features no-p2p,mfp,peer-flow-ctrl,btcoex-param,allows-mesh-bcast,no-ps crc32 ba79b746
[ 26.006428] ath10k_ahb a000000.wifi: board_file api 2 bmi_id 0:20 crc32 e2dfaa91
[ 27.413294] ath10k_ahb a000000.wifi: htt-ver 2.2 wmi-op 6 htt-op 4 cal pre-cal-file max-sta 512 raw 0 hwcrypto 1
[ 27.435282] ath: EEPROM regdomain sanitized
[ 27.435309] ath: EEPROM regdomain: 0x64
[ 27.435323] ath: EEPROM indicates we should expect a direct regpair map
[ 27.435359] ath: Country alpha2 being used: 00
[ 27.435371] ath: Regpair used: 0x64
[ 27.850676] ath10k_ahb a800000.wifi: qca4019 hw1.0 target 0x01000000 chip_id 0x003b00ff sub 0000:0000
[ 27.850741] ath10k_ahb a800000.wifi: kconfig debug 0 debugfs 1 tracing 0 dfs 1 testmode 1
[ 27.864029] ath10k_ahb a800000.wifi: firmware ver 10.4-3.6-00140 api 5 features no-p2p,mfp,peer-flow-ctrl,btcoex-param,allows-mesh-bcast,no-ps crc32 ba79b746
[ 27.911790] ath10k_ahb a800000.wifi: board_file api 2 bmi_id 0:21 crc32 e2dfaa91
[ 29.329734] ath10k_ahb a800000.wifi: htt-ver 2.2 wmi-op 6 htt-op 4 cal pre-cal-file max-sta 512 raw 0 hwcrypto 1
[ 29.352251] ath: EEPROM regdomain sanitized
[ 29.352281] ath: EEPROM regdomain: 0x64
[ 29.352295] ath: EEPROM indicates we should expect a direct regpair map
[ 29.352330] ath: Country alpha2 being used: 00
[ 29.352342] ath: Regpair used: 0x64
A quick test with ath10k-ct also appears to be fine.