Best Practices - VIMEO videos

Hello. I have a website that as quite a lot of Vimeo videos being loaded via iframe.

The Question
What’s the best way to load a bunch of looping videos without having load delays (blanks spaces where images are loading in), and causing unnecessary page load speed decreases.

Should we be using a different format? Load these some other way?

Some notable points:

  1. The videos are hosted on our premium Vimeo account, NOT on our server.
  2. We’re loading them in via “iframe”
  3. They are all set to auto-play and loop like GIFs for the most part.
  4. Our website does have CDN, caching, deferring, etc. enabled.

The Website with a good example of all our vimeos:
https://stable.stable-demos.com/what-we-do/

Example of how we’re loading videos in:

<iframe src="https://player.vimeo.com/video/349969269?background=1&autoplay=1&loop=1&title=0&byline=0&portrait=0" width="640" height="427" frameborder="0" allow="autoplay; fullscreen" allowfullscreen></iframe>

Thanks in advance!