Sharepoint Crawling doesn't auto run as per schedule.

Jason120 Running a SharePoint on-premises is very involved.

Based on your posts (i.e., the WSS_Content - using defaults, not knowing how to read ULS logs). So far, I gather that you are very new in the SharePoint world. And, I mean no offence by that. We all have to start somewhere!

The images and the errors I am seeing look like there's more issues in your SharePoint Farm than just the search service application. 

You may want to take a look at this book Amazon.com: Deploying SharePoint 2019: Installing, Configuring, and Optimizing for On-Premises and Hybrid Scenarios eBook : Catrinescu, Vlad, Seward, Trevor: Books - I have no affiliation to these guys, but they are both well known in the SharePoint world.

Perhaps consider getting some assistance by using a contractor/consultant (specifically an architect) to begin your SharePoint journey as it could be overwhelming to maintain for beginners. If you do end up hiring help, make sure to work with them closely and ask as much questions as possible, get them to generate the build books, information architecture, etc.,