There's a good general one at https://tubefree.org which already carries many long original interviews by the owners of the instance. I'm sure they'd be fine with others uploading interviews too.
Also if you are okay paying for hosting might be worth considering your own instance through something like @fedihost , it's a lot cheaper than people realise (https://fedihost.co/hosting/peertube).
More info about both these options at https://fedi.tips/how-to-publish-videos-and-audio-on-peertube