You can use HTML/CSS but HTML/CSS can’t run PS code on its own as I’ve stated a few times (as far as I’m aware anyway), which is why i mentioned C#. This is also why people are suggesting you use tools that are already out there, (like the MS provided one), as people-built tooling to allow building of solutions for this kind of situation. Like the MS provided web form, JEA is another tool provided by MS.
To answer your question about JEA:
JEA stands for Just Enough Administration, and is a technology or feature in PS. Lots of resources that explain it better than I could, definitely recommend searching online for it some. A few links to get you started::
Overview of Just Enough Administration (JEA) - PowerShell | Microsoft Learn
Using JEA - PowerShell | Microsoft Learn
I mentioned WebJea as well… here’s a direct link:
GitHub - markdomansky/WebJEA: WebJEA - Secure Self Service Web Forms from PowerShell Scripts
I mentioned PowerShell and C# w/ runspaces… again another link:
Runspace01 (C#) Code Sample - PowerShell | Microsoft Learn
(Note: this stuff was all pretty easily searchable using terms like ‘powershell AND jea’, ‘webjea’, and ‘powershell C# runspace’)
If you aren’t super comfortable in .NET or have some skills programming, my concern is that C# is going to be a bit of a barrier to entry. That’s where @tonyd 's suggestion comes into play, and you can simply use the MS part, and not worry about the PS. then you just modify HTML/CSS (which you’re still learning when you do that. However, we won’t be able to answer any HTML/CSS questions you have, we’re a PowerShell shop 
You just need to figure out what you’re trying to focus your efforts on and go from there.