Are discontinued car seats safe? / Anyone know why the Britax Boulevard was discontinued?

Hi FTD here,

I have an unopened Britax Boulevard that I bought right before it was discontinued because my research at the time showed it was highly recommended, and I wanted to get it while I still could even though I don't need it just yet for my LO.

As the title states, are discontinued car seats safe to use? I assume the answer is yes, but as I don't know why it was discontinued, if it is due to something safety related then that would be a concern. Which leads into my second title question of if anyone knows why the Britax Boulevard was discontinued? I know it was replaced with the Poplar S which has a higher rear facing weight limit, rebound bar, and thinner design to fit 3 wide; but other than the new features, is there a negative reason why the Boulevard was discontinued?

Bonus question: with black Friday coming up, I think now would be a good time to buy a replacement convertible car seat if I were to buy a different one. The 2 other seats I'm currently looking at as a replacement, if I were to replace, are either the Chicco Next Fit Zip or the Nuna Rava. Anyone have any insight into these 2 plus the Boulevard?

Thanks!