Got it. Well, your post covers a couple of very common questions asked here in the Community.
1. Symbolizing by related tables.
Unfortunately, this isn't possible using a layer and separate table, even if there is a relationship established between them. The symbology profile in AGOL does not support one feature accessing the attributes of other features or layers. In order to use the table's attributes to symbolize your features, you'll need them to be "baked in" somehow.
One way of doing this is to perform a join in AGOL using the Analysis tab. You could also attempt to create a hosted view layer using an attribute join. In your case, you could join this based on both the province and PIN fields together. This is a good option, as the hosted view layer remains up to date as its parent layers are edited / updated. No need to re-join and replace your layer, and the output view will behave as though the source attributes were all in a single table, which, importantly, allows you to visualize based on the joined fields.
2. Automatically refreshing from a Google Sheet
This is a very popular question on here. You can find lots of similar posts detailing different iterations of the problem, but yours seems very straightforward. If the updates are only coming one way (Google Sheet → AGOL table), then you should be able to publish the sheet, and whenever you need an update, click Update, then Overwrite.
You'd have to do this manually, unless you devise a means of automating it using the ArcGIS Python API. Doing so is not difficult, but may be a bit much for something that's just a few mouse clicks every month.
Final note: to make this easier for joining / updating, make sure that the parent layers are separate items in AGOL. Having the table and spatial layer in a single service would risk something going wrong in the spatial layer when overwriting the table.
- Josh Carlson
Kendall County GIS