1. Regarding your thin river value bets.

A)Create a filter in HM where you select some marginal made hands on the river (E.g. low pair/bottom pair - TPWK) Select 'bet' as your river action. Go to the 'Hands @ Showdown' report. If your W$SD% is less than 50% you should definitely be checking back instead of betting in this spot.

B)(If it is pretty close to 50% you should also do a filter to see how many times you bet-folded the river & factor that in. A bit complicated but if you W$SD% is 50% out of 400 hands in filter A) and you bet-folded 100 times as well this means you only got paid off by worse 200/500 times you bet the river with a marginal hand or 40% which would mean you are better off checking more often.)

(Obv. calling on the river is dictated by pot odds but betting last to act we need to be called by worse 50%+ to be +EV excl. metagame.)

2. I'm guessing you are semi-bluff raising a lot of draws GS+ so you win a lot in non-showdown winnings when they fold but you are usually a slight underdog when all the money goes in. Just do some filters where you select the draws that you often raise on flop/turn and compare the BB/100 of raising with calling and folding. (Obv. you should still be bluff raising a fair amount for meta-game.)

3. It is natural for peoples red lines to improve and their blue lines to go down as they move up stakes and play harder competition.
Weaker players generally go to showdown too often, ergo you have less fold equity vs. them (Bad red line) but they pay you off with weaker hands more often (Good blue line) & vice-versa with stronger players. The only obv. advice I could suggest there is make sure you are table selecting well & getting involved in more pots with weak players (pay you off more = better blue line) & maybe avoiding really good regs with marginal hands.

4. Finally the thinner you are capable of VB the more your red line is likely to go up which you have already explained.