802.11ac is a larger difference to 802.11n, than 802.11n was to 802.11g, both in terms of effective throughput and range/ throughput over range. This also results in better bandwidth utilization, taking exclusive ownership over the frequency for less time.
The aforementioned chipsets are PCIe wireless chipsets, not SOCs - accordingly there is no CPU performance involved. In terms of SOCs, this would technically correspond to the "Honey Bee" (QCA9531, QCA9533), "Scorpion" (QCA9550, QCA9556, QCA9557, QCA9558) or "Dragonfly" (QCA9561, QCA9563) chipsets - however (aside from low-end single-band devices), these rarely come alone, without a corresponding (ath10k) 5 GHz 802.11ac radio. If that's to be avoided, you'll need to go older, probably down to "Wasp" (AR9344, usually combined with AR9580 "Peacock" 5 GHz radios). The TP-Link TL-WDR3600/ TL-WDR4300 (8/128) would be one specimen of this generation.
However I would not agree that this would be money well spent in 2019, on the brink to 2020 and 802.11ax. MIPS based Wasp or Scorpion are no match to the ARMv7 based Dakota (ipq4018/ ipq4019) chipsets.
 Not the least because early draft-n silicon (e.g. "Howl", AR913x) was both seriously underpowered and suffered from quite a few nasty silicon bugs. This was less of a problem beyond the failed QCA9880-AR1A for 802.11ac devices.