@ProSumerTester Hard to say if that is good or bad without knowing things like how far apart the APs are, what type of building material is in-between, how many other APs from neighbors are overlapping, what the receiving signal quality is like, and are other local devices using older wifi standards such as n or a.

Suggestions to try to improve, use a channel set that is least used by neighbors, us a phone wifi scanner to see what channels are in use.  If you can move the APs a bit, set them so there are fewest wall/floors between.  Look up the AP's certification info for highest transmit power band, for US FCC certification that is the upper 5ghz, but EU may be different.  Set the minimum connection rate higher to exclude older devices.  Lastly, find a way to get a wire there.

  @ProSumerTester A signal strength of -60db is low, so the 150meg is a good rate for the signal.  With them being on different floors, it would be best if the upper floor AP is the wired AP, since the signal transmission pattern is around and downward (when ceiling mounted).  If the lower level one is wired and not covering another floor below, you could try flipping the AP upward.  Also try changing the channel used to the other end of the band (e.g. if using a high channel number that might be power limited, change to channel 36).

As far as phone wifi scanner for Apple, I've only ever used Android, but UniFi's Wifiman is pretty good and looks to be available on Apple.

  @ProSumerTester I see, if possible try moving AP1 to point downward towards AP2.  Also see about mounting AP1 away from the tv stand, as furniture will also reduce signal.  And a 4dbm increase in signal is pretty good (that's 2.5x the signal, but magnitude is still pretty low), that should get you close to 300mbps.

  @ProSumerTester  It may not be feasible for you, but if you have a cable that will allow you to put the EAPs in the same room so that obstacles are not an issue, you could then test speed. This way you can see if you are just chasing a rabbit. Personally I have never been able to come close to the specified rates on our EAP610 / EAP225 MESH, and figured out it would not happen after putting them in a best case scenario. I stopped chasing the rabbit and installed another solution that delivered to spec under the same conditions.

Not saying they can't deliver, but test under best case. That way if it does not deliver, you can look to see if the issue is elsewhere and decide what to do from that point.

  @ProSumerTester 

Just to jump in here with my two cents

Bear in mind that this will never be as quick as the main AP, simply due to the half-duplex nature of WiFi.   Each "hop" will half the speed (roughly)

Given AP1 on 5ghz is rated for 866mbps, this is likely to be ~450/500 in real world speeds after you take loss, overhead etc..    As you are Mesh the AP connected via Mesh will get roughly HALF that again at AP2 due to the half-duplex over carrier.   Therefore as a finger in the air guess, one would imagine speeds around 200 / 250 at AP2

That's purely based on personal experience over too many years..

Also the smallest changes in DB can massively affect this, -60 is kinda MEH / Average.   If you can get this to -55 or even -50 you will see a vast speed improvement.    As mentioned earlier in the chain, every 3db is half the signal gained!   

Generally, this is the accepted range..

-30 Heaven.. you will only get this in a lab

-40 Best possible signal

-50 Good signal, well workable

-60 Average signal, average speeds

-65 Low signal, slow speeds.. This will be frustratingly slow.

-70+  Will connect, but wasting your time

  @ProSumerTester 

I do not expect speeds like accessing AP with out mesh but was hoping to get at least 300 Mbps.

Thank you for dBm values explanation, will aim for lower value if possible.

If you have completely clean airspace (little interference) and using one of the DFS channels, then its possible you could push close to 300 over MESH with AC WiFi (WiFi5)

However from experience its very rare, usually I see ~230 as the normal speeds with peaks at 250ish.    Best way to test this, whatever you get at the ROOT AP, then half that per hop is a good estimate.   With an AC ROOT AP one would expect 450 to 500 Mbps so half that on the Mesh

Going to WiFi6 would get you the speeds you need, however it does increase the price!