I see a number of comments here complaining that these apps cost money on the Play Store. To all of you, I say, the developer of these apps owes you nothing. You are entitled. These apps are a product built over a period of years largely buy a single developer. This developer has chosen to embrace Free Software and releases the entire source code to the pro-versions of these apps in order to allow you both audit them and build them yourself or fork them if you choose.
I only use F-Droid (which has the full versions gratis) so I donated to the developer's Patreon (until I switched to a Pinephone).
If these apps were proprietary, would you be entitled to them gratis (free of charge)? How does the developer granting you access to the source code change this?
If you use and enjoy these apps, please consider donating to the develop's Patreon in order to support them more fully.