I am surprised that people aren't using google colab pro/pro+ in this context. You basically get access to multiple A100 for $10/month and with some simple javascript tricks, you can get a session to last for 24hrs at least.

Pro+ is more expensive at $50/mo but it allows for more simplified background execution. if you are only just getting started and don't expect to be training for multiple months, then colab or other cloud-notebook providers are really great to start.