I have changed my mind about RT-AC86U. I do not recommend ASUS routers to anyone anymore.
My first Asus router was n66u and now I have ac68u, both were running Merlin + entware (To be precise, I switched to john9527's awesome fork on the n66u when Merlin "abandoned" it).
I never had any issues and it is simply pure joy to use these units with Merlin's FW, I could never go back.
In previous years, I deployed many N18U units for friends and in the family (talking about more than 50 routers here), and lately I mostly deploy AC65P units. Both were exceptional "bang for the bucks" devices (the ac65p truly is), and it really saddens me that I had to go OpenWRT with both since Merlin does not support them...but to the point:
the only problem I ever had with any of those routers is 2-3 power adapter failures, and that is it for hundreds of deployed units!
Yes of course, networking is cool and I'm also an enthusiast, I understand that soho routers have many shortcomings. I also bought an ER-4 and a GS108Tv2 along with some UAP-AC Pro APs to play around at home, and those are awesome indeed, but also an overkill to be honest. There is simply nothing what my ac86u could not do (with some tinkering) what a home user would need.
I agree that Asus (just like all the other big brands) are dropping quality rapidly in the last few years, but my personal experiences are vastly differ from yours, and - for home use - I personaly still prefer anything what Merlin supports.
edit:typo
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