Emulate old consoles in Xbox One

Hello people and welcome to the third episode of me asking info because I may want to purchase a Xbox console.

This time I made several deep verifications (at the point to compare the number of ports on the different models) and I'm almost sure I want to buy a Xbox One S.

Consider I'm in Europe and the price gaps among the different models are not the same that are in US, long story short, I can get a used One S for 100-120€ against 289 of a Series S, while a One X used would be from 200 on.

What I want to do with the console?
I want to play games from various Xbox generations:
-Two of OG Xbox, GTA San Andreas but especially Panzer Dragoon Orta (that's the main reason why I am interested to Xbox).

-GTA 4 for 360

-GTA 5. For these, two versions exist - 360 and One - with One version being way better afaik.

-MGS 2 and 3 HD collection.

The big problem is: I don't want to buy a big console for just 6 games! Both for the space and the money, also there are very high chances that I will not use it much in that case.

So the element that will drive my decision in the end is if I can use it for emulators, as it will increase the chances for me to use it.

In my first post (https://www.epforums.org/showthread....54#post1940454) in which I was considering to buy a 360, I was answered that a One is way better to do all the things I want to.. but Emulators could be played (in 2019) only with the Devkit mode, which precluded the access to Retail games (but I wanted both the thing, not to renounce one or the other)

In my second post (https://www.epforums.org/showthread....20#post1982120) I was considering the idea of a Series S, but again was suggested to opt for a One (X, but I don't really need that).. idea that now I abandoned as it's Digital only and I still want to have the physical drive, both because I want to have physical copies of the games but also because the possibility to play movies on DVD and Blueray is another small feature that may increase the opportunities to use the console.

So, in the past days I collected info about the emulation, also comparing again the various generations (especially 360 against one, since also 360 may do all the things I want to.. but it requires to be modded which may be at risk of ban, so since One does everything also better, I would rather invest on it), considering I'm also reluctanct to buy a devkit and found the following:
-Initially, I read that Retroarch could be installed in Retail mode, but since it was banned by Microsoft store, it was set as a private app, so you provide your account email to the developer and they grant you access..

-Then, while asking confirmation for it in a Discord server, they told me that now it's not necessary anymore, since they are inserted in the indie store that is accessible in Retail mode.

So the question I'm opening this post for is to have confirmation that this is true and if so, cab you confirm this is licit and I won't risk to be banned?

If that's the case, I will buy the console.

I take the chance to ask another couple of side questions:
1. If I buy og Xbox and 360 games in physical copy, it will be sufficient to insert them in the One to play them? I recall the disc was used to recognize you had a licit copy and then a digital version gets installed in the hard drive. Is it correct?

2. I might be interested to have the Kinect, but heard the One S doesn't have the port and needs an adapter. What cool things can Kinect do? How much the adapter costs?

I apologize for the massive test and thank you in advance for your precious time and help!