That damn round 0 bye is the easy answer to this.
I ignored it last year and it absolutely derailed my season, you can just can't be throwing points down the drain over the first 6 weeks that are easily avoidable. It was obviously compounded immensely by how hot the best non-r0 guys started last year (Butters, Houston, Serong, Ryan, etc) but it was a huge strategy error.
I'm going to basically factor in that anyone with that round 0 needs to be a confident 10ppg better than any alternative as my rule this year, which basically is the 50 points lost from their bye (110-60) over the first 6 weeks to be even/ahead. I doubt there will be many premiums that this stacks up for, if any. There will be a few midprice guys like Day and Newcombe where it probably does become a worthy discussion though. Bailey Smith has been in my drafts so far with the bye for example.
I would argue the opposite. It's best to start players with a poor injury record than trade them in if they start on fire.
The injury risk is still there but now you have used a trade to bring them in and potentially have to use another if (when) they get injured.
However, with the number of trades we have these days and the Flex position this is less a concern than previously.
I had Rankine in my first picked side. He's not there now but will likely find his way back.
I think your logic is sound but my experience the last few years of ignoring this because we have so many trades has been that the compounding impact of the lost upgrades is far greater than the benefit.
If you upgrade in to them, then the replacement trade is more likely to be one of the "extra" trades rather than derailing you in the upgrades.
There's obviously perfect examples for both of it going right and it going wrong, Treloar or Whitfield last year for example would have been great choices on either starting or trading in to. Heeney, Crouch or Touk were clear examples of starting wins and upgrade fails. Josh Kelly and Taranto stand out as disasters to start. English was a bit of a disaster either way but worse to start because of the cost.
And then of course you've got the likes of Petracca where you pick them because of their durability and get smoked on it which seems to happen to 2 or 3 guys every season and those ones feel even more devastating, especially when you pick them over someone primarily on that factor!
Will go with the same rule of thumb that the preseason is the best indicator of durability, it tends to be the same guys that have issues in preseason and then the real stuff, definitely a few guys I've ruled out though at least already just on not worth the risk.
It really is striking how important durability is though, of the top 27 averages, only two of them played less than 21 games last year and the two below, both 19 games, were 19th and 25th in the group. As you get in to that next 25 or so guys, the games missed tends to start to get a lot more random despite plenty of really talented guys.
Hardest thing I'm finding so far on starting sides is trying to balance the round 12 bye. Probably because it's 4 teams that dodged the round 0 bullet, but finding an extreme overload in those teams for the guys that I want.