throughput + WiFi is not something which can co-exist without running in to problems. So you need to work out a sound plan. Wireless is a very sensitive media, due to non-tangible nature it is prone to interference which we cannot identify easily (even 5GHz), interference could come from your own wireless infra or from another source. I would say get professional help to plan and design the setup and conduct a onsite site survey to study the RF propagation to recommend AP positioning and usage of antennas. That being said below is a very high level of things I would follow, but adopt only after studying your setup and preferably after a survey
1. Run the latest cisco recommended AireOS
https://www.cisco.com/c/en/us/support/docs/wireless/wireless-lan-controller-software/200046-tac-recommended-aireos.html
2. Use latest model of AP's. Vendors always put their best effort to for design and testing of their top of the line products. If budget allows, and the requirement can be justified against the cost please go with the top of the line AP's.
3. Always try to have the latest wireless drivers for the connecting clients. I know it is difficult, but if you have centrally managed devices please go ahead and upgrade them tot he latest.
4. Read the release notes of the product and the software, understand the bugs proactively and apply the workarounds.
5. Do not use AVC if the WLC is fully loaded, this has a rough impact of 30% on the performance of the WLC. If you need to mark MS teams traffic you will have to use this feature, but please study the limitations before implementing.
6. Do not use FRA, if it's not thoroughly tested or if you don't have a sound RF plan.
7. Do not use wide channel widths. Always try to go for the narrow channel width's as this will provide you with more channels in 5GHz. Using 40MHz in 2.4GHz is not recommended at all.
8. Selectively turn off 2.4 GHz radios. After doing the changes conduct a site survey to verify that there is sufficient coverage.
9. Use band-select for SSID's. This will steer the clients to 5GHz radio.
10. Do not use hidden SSID's. This doesn't increase security and it will create lot of issues for certain clients like roaming etc.
11. Enable Fast SSID change.
12. Follow RFC5737 for configuring the virtual IP
13. Enable client load balance in WLC, but please note this can have some issues with certain clients. Test it before enabling.
14. Enable 802.11k,v. For FT make it enabled and use over the air, dont use adaptive.
15. Keep the maximum number of SSID to 3, use dynamic VLAN assignment using radius if required to segregate clients based on the VLAN.
16. Disable all lower data rates. All data rates below mandatory must be disabled. You may have to test in your environment what is the best data rate to set as mandatory.
17 . Use clean air and ED-RRM if AP's support.
18. Do not use 10mins for DCA timer. Increase it to minimum of 4 hours.
19 . Make use of the DFS channels and all other channels allowed as per your regulatory domain.
