First time using GPU Encoder, and it failed?!

I have been making Shotcut videos for 3-5 years now. Previously, I was using an old Dell til abou 3 years ago, when I got an ASUS Rog series. I have an ASUS w AMD Ryzen 7 5800HS, w Radeon Gfx 3.20 Ghz. 16 GB Ram, It’s a gamers machine, and seems to do well making my Shotcut videos for 3 years now. I’m on YT and growing, if anyone wishes to find me, look up Daddy3Dman81, I play games online.
ANYWAY… I have not used the option to use Hardware Encoder on the Export tab, til recently. I always thought that referred to an external sound board/ video editor board you would use in a studio, and if a Shotcut PC was plugged into those, that was an option. I recently came upon a YT video explaining Shotcut rendering options as I am always trying to grow my knowledge, and the YT’r explained that the Hardware Encoder checkbox would boost any 2nd GPU for rendering the video, and I thought that would be Useful sense I have a gamers PC with a 2nd GPU.
So i tried it, using other options H.264 something, I think. + I checked the Hardware Encoder tick. The video Rendered! It seemed to complete the job. However, just a rough draft of my project, close to an hour video. I watch the video in Win Media using OBS to record voiceover and keeping it aligned, and watch it all the way through. Everything seemed to be working. Video was playing. OBS was recording. I was talking into mic, and suddenly Win Media video stopped, white screen, and said something to the effect (Paraphrasing), Unable to continue. Unable to support encoder settings." or something like so!

Initially I thought all was lost with this video! It’s not, it’s just a rendered rough draft, I can go back to the Shotct project before render and redo! It’s just a set back.

I want to know if someone can explain, what went wrong?
Was I mislead by YT"r to thinking I could render with Hardware Encoder using the GPU?
Was it using OBS to watch, record voiceover which seems to have had a better result than Audacity, as the voice over stays aligned with video entire length? Although I have audacity still, I haven’t used it in a few months, sense I had OBS. Was changing the Encoder setting from Youtube to H.264 something (forgot which option it was) possibly the culprit?
Was it Win Media, not able to read the video MP4 which hasn’t given me any problesm before this, with other videos?

It seems like it all goes back to using Hardware encoder, but I’m trying to understand if that was the mistake, or if something else I should have done/not done, to support the Hardware Encoder option, and that was the problem?
Daddy3Dman81 on YT
Call me Dman, D, or Derek.

Edit… It came to mind afterwards, but I should also mention, all my project files are on a NAS WD My Cloud storage connected to my Router, accessed by computer through WiFi. It’s a personal storage cloud. I’ve been saving files there, using, and reading files, making new files. etc. Including the Mp4 that failed. Both Shotcut, Win Media, and OBS Studio operate off my PC, reading the files needed on NAS and rewriting as needed back on the NAS. IDk if that would make any difference to the project. They’ve been fine doing that for many months now, and Haven’t had any issues sense! Til this one. Again, I wasn’t sure if it would of had any additional implications causing the problem, just thought I’d mention it.