Rejuvenating my MacBook Pro (Retina, 15-inch, Mid 2014)

Hi all, (This is a repost of the following on r/mac [Rejuvenating my MacBook Pro (Retina, 15-inch, Mid 2014)](/r/mac/comments/1hx94jz/rejuvenating_my_macbook_pro_retina_15inch_mid_2014/)) I've been using this baby since 2015, largely for word processing. So, before I continue (and if it even is relevant) I don't intend to replace it anytime soon since the resale value will be quite low and it still serves my use case just fine. However, it takes much longer to restart/shut down and boot up, even with a decent 500Gb SSD. As such, I've been wanting to do a fresh install of macOS Big Sur V. 11.7.10 (20G1427) (which, as I understand it, is the latest OS I can run on this baby) in the hopes of optimising performance, especially when it comes to indexing (Mail is just ridiculously slow these days and it's frustrating to use). Here's where I need advice: I've got an up-to-date Time Machine, so - in theory - I can do a clean install and just restore everything after, but my theory is that it won't really improve anything in the long run, so the question is whether I just copy all of my crucial documents/files/software onto an external drive, and then go for a fresh install and copy everything across when I'm done... Here are my specs: *MacBook Pro (Retina, 15-inch, Mid 2014)* *Processor 2.2 GHz Quad-Core Intel Core i7* *Memory 16 GB 1600 MHz DDR3* *Startup Disk HDD* *Graphics Intel Iris Pro 1536 MB* Any protips and thoughts? (I know this isn't a Windows machine, so in theory fresh installs shouldn't really do much, but I just wanna give it a try, since my Mac used to be way snappier, and I'd love to regain some of the punch it used to have.) Also, I'm not sure this is the ideal sub to post this question on, so I'm happy to (cross-)post to other subs that other may recommend. Thank you!