Have you considered keeping them on YouTube but unlisted, so that they don’t show up on your profile nor in youtube searches?
Otherwise, you could create a Google Photos album, but either quality suffers, or the videos will take a lot of space.
All the other options I could suggest either call for a recurrent payment, but trust me, it gets tedious after a while (ie. VPS with Peertube or similar), or call for losing quality by a lot (ie. Whatsapp or Telegram channels/groups), or quickly become unpractical (ie. Mega, Dropbox…)
There are plenty of choices, and if you’re 100% sure you’re fine with recurring payments and having to constantly mantain a system/keep it updated and secure, then go ahead and make a VPS, but if you’d rather have it be convenient, look into additional YouTube settings or common alternatives like Vimeo.
Have you tried Qt but with QMake instead of CMake?
Use Qt Creator instead of Visual Studio.
It is much much easier to manage the project with QMake in my personal opinion, and Qt Creator blends beautifully with the Qt Framework with the kit manager, and the form designer, qmake/cmake integration…
Qt (Framework) manages so much behind the scenes that cross platform is trivial.