Another possible issue is use of (relatively) high frequency - 5745MHz ... which defines center frequency of control channel, in your particular case (with Ceee) this means lower part of whole channel, which with particular settings would ideally span between 5735MHz and 5815MHz. Not all devices (your cAP ac might be included) support those upper parts of 5GHz band. Try using something lower for test.
Another issue with those higger frequencies is lower legally allowed Tx power ... which reduces range and throughput (at medium distances).
Why aren't you showing the actual performance metrics? You're only showing theoretical settings.
Show us the speed at which the device is connected via cable—it might be 100 Mbps. Show us the log table with the client device's connection parameters. It's possible that this is the maximum speed the client can achieve.
After coming back to this topic and rechecking everything I see that my server dropped its link to 100M...
I am 100% sure that was the first thing I checked. In setting up iperf I confirmed a working Gbit connection with ~950Mbits.
Well, now I get 270Mbit/s with my cAP ac config from the first post.
I started this quest by updating my Mikrotik Hardware to RouterOS 7.22.1. I did this with a manual Update and had a bit of trouble finding the right package for the wireless part. wifi-qcom does not fit on the cAP ac. The download page has no clear information on what to use. Should I try again with wifi-qcom-ac?
This a my current config and I get 270Mbits to the test laptop from before and 330Mbits to my hAP ac.
I am building a bridge between the cAP ac and the hAP ac.
I was confused that /interface wireless monitor wlan2 still says 5180/20-Ceee
In short: your AP is using 80MHz channel just fine.
Longer description:
AP is using standard 20MHz-wide channels (non-802.11 APs can operate using narrower and/or wider channels). That's done this way to provide backward compatibility for stations which don't support widest offered channels.
AP is using 4 contiguous channels ... making total channel width 4*20MHz=80MHz. Channel layout is "Ceee" which stands for "Control-extension-extension-extension" (and that's the layout that most stations are comfortable with).
In theory, there has to be one Control channel (to provide compatibility with 20MHz-only devices and 20/40MHz devices). And that Control channel can be placed anywhere in the contigous channels used (so "Ceee", "eCee", "eeCe" or "eeeC" in case 4 channels are used). In practice, most APs (which don't offer flexibility that ROS does) and many (if not most) stations like/use "Ceee" layout.
Depending on "center frequency" selected, not all channel layouts are possible - if center frequency is set close to boundary of allowed frequency limit, e.g. 5180 in your case, then some channel layouts are not possible (because they would reach outside legally or technically allowed frequency span). E.g. "eeeC" with 5180 set as center frequency is not possible because that would mean frequency span starting from as low as 5110 MHz which is outside allowed frequency span for 5GHz WiFi band.
Frequency 5180 is used as center frequency of Control channel. Actual 80MHz channel set then spans from some lower frequency to some higher frequency, depending on Channel layout (see previuous bullet). In your particular case that means that channel between 5170MHz and 5250MHz is used. Center frequency of actually used frequency span (which can be different for different stations, connecting to your AP) can then be either 5180 (for 20MHz-only stations), 5190 (for 40MHz stations) or 5210 (for 80MHz stations).
. It it was running wifi-qcom-ac, it would start to breathe