The uhd 630 is pretty good but it is old enough that it might have some codec limitations. I think it was the first generation with full H265 10bit support so your 4k hdr rips can be transcoded if need be.
You should be able to manage 4 or 5 simultaneous 4k to 1080 transcode and at least 10 (likely more depending on bitrates) 1080p transcode streams.
It is still best practice to avoid transcoding wherever possible, but if it is needed it should be quick and seamless on that chip.