Why does my phone barely charge?

This is my first phone, so I don’t have much ownership experience. But I am a software developer who’ve used phones in software development since 2012.

I purchased the Google Pixel 2 on August 15, 2018 - and after roughly 10 months of use, the phone started having difficulty charging. I figured it was the charging assembly in the phone as it seemed like I had to push the cable further and further into the phone in order for it to charge. After a few months of that, I looked at the cost of the tools and parts to fix it myself and found it too expensive at the time. So I tried ordering a new charging cable and a new charging adapter. The new adapter wasn’t a fast charging adapter but it worked a lot better than the fast charging one - but the new charging cable was no different.

And I stuck with that solution. A few months back it started getting harder to charge it again, but I was increasingly careful with not using much force or bending the cables, and it seemed to last. Until about a week ago, that is, when my setup started to suddenly take 24-60 hours to fully charge, from about 4 hours. I got a new adapter and cable under warranty, but they haven’t made any change, so this time I figure it really must be the charging assembly.

But before I order it, and the tools, I wanted to ask on here if one of you more experienced people think that my assessment is correct, and to ask for some recommendations to diagnose the problem further, if any.

I.e. should I just try to order the tools first, and then see if the charger is just misplaced within the phone or similar? To me, it does seem like it has been pushed further in that it should be.

Looking forward to your replies. Happy holidays and new decade’s eve.