Google console saying pages are not being indexed and also options for customers uploading photos

[ScottishC]

The problem is Google search console  reports saying that 329 pages are not indexed because of "alternate page with proper canonical tag"-(saying it is a website issue) but I am NOT going to worry about that because of what experts have previously posted.

HOWEVER a further 305 are "crawled not currently indexed" (which is a google issue) then 4 are "Not Found" and 4 are "Blocked by Robots" (website issues)

I see these issues have come up before and pointers have been provided but they involved inputting bits of code in head section -blah blah all gobbledegook and I am not technical and will need someone to actually fix this for me. 

The number of "not indexed" pages has halved in 2 months (sounds good?) so does it need fixing at all or should I just wait?

When outsourcing am I asking a web developer to fix this, or specifically SEO experts?

 Is this quite a quick fix, what are we saying here-half an hour? a couple of hours?

Secondly- I want to improve my offering by allowing customers to upload a photo which can be applied to a product-however I foresee a lot of problems with this, so would welcome suggestions as to how to manage this and avoid inappropriate or poor quality content..(maybe a tick box disclaimer?) and appropriate app suggestions for Shopify Dawn theme please.