I would definitely recommend giving the Microsoft Applied Skills a look:
https://learn.microsoft.com/en-gb/credentials/browse/?credential_types=applied%20skills
You can filter the first URL of the applied skills overview to your desired areas and see if any are of interest. They are constantly adding more to do so keep an eye out.
Whilst the current crop of applied skills exams don't seem to have too many options for SC-300 it does have other content that the AZ-500 may be applicable to.
Best of all, these are free to do and provide real labs with real-world scenarios. You're then scored at the end automatically.
So for example, if you do the one above you'll be given a lab VM (free) during the exam and be asked to complete tasks to validate your skills. These applied skills are not proctored and if you do not pass you can retake 24 hours later (see here for more info:https://learn.microsoft.com/en-us/credentials/support/retake-policy)
Whilst these aren't labs, they are free and as close as you can get without having to provision yourself in Azure. I would recommend choosing a few and using the study material before trying them so you go in with some confidence.
As for your second question, this may be best posted separately so it can get the attention from those who will know the answers for you due to the title nature of this one.
If this answer was useful, please feel free to mark as accepted.