Have you tried both the keyboard and controller modes on the shield?
I found Bluetooth the better option to connect to the shield versus 2.4ghz. I use https://www.amazon.com/gp/aw/d/B07T13GLY3/ref=dp_ob_neva_mobile
Has a TouchPad, back-lit, scroll wheel. I like it.
(Upgrade) Rii i4 Mini Bluetooth Keyboard with Touchpad, Blacklit Portable Wireless Keyboard with 2.4G USB Dongle for Smartphones, PC, Tablet, Laptop TV Box iOS Android Windows Mac.Black
It's not the same one, but I would assume pretty close
I use this for my htpc and tv. https://www.amazon.com/dp/B07T13GLY3/ref=cm_sw_r_apan_glt_fabc_6TPZHM41SYPVT6KXR9TB
For web browsing on the fire stick I use a sideloaded Kiwi Browser with uBlock Origin and Poper Blocker as extensions. Along with a VPN it's pretty decent at filtering pretty much anything. The caveat is you will need a way to enable a mouse on screen to use this type of browser since it's not made for TVs. I use this Rii i4 BT version
I like it more than the Logitech keyboards, gyroscopic remotes, a media server remotes that I've tried in the past. I returned it to Amazon at one point because I had a few other touchpads and keyboards in the pipeline but after weeks I missed it so much I bought it back. That damn little mouse wheel (the little red thing on the right) is so convenient.
For youtube, obviously a modded ad-free youtube like Smart Youtube, Youtube Vanced, or Smarttubenext is best just to get the ads out of the way. I believe there are other open source projects out there as well.