I'm sure that I'm beating a dead horse with this post but can somebody help me to figure out how to speed up Photoshop and Lightroom running on my Late 2015 iMac? My iMac is a i5 4 core 3.2 ghz model. I'm currently running Big Sur and I think that it is particially part of my problem but I've noticed PS and LR have been getting slower on my iMac for years now. My iMac is running with 32gig of ram and that did help a bit when I installed it years ago but now days after opening LR just touching a photo causes the colored pinwheel of death to start spinning for about 30 seconds sometimes longer. Saving large files from PS is painful, sometimes I just have to leave the room and good get a drink of water to pass the time.
An Apple Guru, who is a friend, suggested I install an SSD into my iMac and place the hard drive into a Thunderbolt chassis and install PS and LR there to speed things up. Another friend suggested loading an older version of MacOS and LR and PS onto an external Thunderbolt drive and boot from there. I really don't want to crack open my iMac if adding a super fast external drive would help. What do you folks think?