I am currently using GoogleChromeLabs/svgomg-twa as a base for my project.
Is there a way to add AdMob interstitials or banner ads within the project?
It is possible to add AdMob to an App that uses Trusted Web Activity, but the ads can only be displayed in native activities - they can't be added to the Trusted Web Activity itself.
Web based ads libraries (eg: Google Adsense) will work as expected inside a Trusted Web Activty.