Important dis/reassembly info on these iMacs are here
These iMacs have double sided tape that glue on the screen. A really thin plastic tool shaped like a pizza cutter wheel is needed to cut this open SLOWLY! to avoid risking cracking the glass. Top 2 corners have gaps between tape strips for a good starting point.
Online available double sided tape advertise themselves for retaping the screen and looks the part. However qualify of the adhesive is suspect and many screens have falling off and cracked later. Professionals also use heat, roller and surface adhesion primer to improve the bond.
This guy put silicone sealant on the 2 upper corners. Note his sealant might have sealed off the air gap on the corners so consider applying it slightly offset to leave air gap intact
https://youtu.be/BNgijy-9W4s?si=r2uEV5bLkPLc0Fkv&t=869
Tesa tapes are really sticky. However, they are not foam core so future removals are potentially impossible. One consideration is to apply maybe 2-3" of Tesa tape on top edge both sides to give it additional strength while maintain removal ease in the future. However, if thickness differs from the foam tape, then one will weaken the other.
<=2010 iMacs has custom thermal sensor circuit. SSD replacements do not have these and fan will spin at max speed. Simple workaround exists
2009 can just jumper the 2 HDD thermal sensor wires https://logi.wiki/index.php/iMac_HDD_Thermal_Sensor_Bypass
Personally I have alway used the 3904 transistor trick for <= 2010 iMacs (and just the remaining 2 legs into the connector + secure with kapton tape).Note all these workarounds aren't creating a temperature sensor. Just setting to a default low temperature so fan doesn't spin at max. SSD will not need much cooling so not an issue.
2011 iMacs have thermal sensor build into the HDD and SATA bus to access. Easiest way is to run free software MacsFanControl (app running under macOS). However, during macOS installation, fan will be loud. Here is a more advanced soldering solution for 2011 iMacs
https://logi.wiki/index.php/iMac_HDD_Thermal_Sensor_Bypass
>= 2012 iMacs have no thermal sensor requirement changing to SSD.
These have been known to have problems with SATA II iMacs (< 2011s). Some 850 EVO for sure.
https://forums.macrumors.com/threads/2011-imac-wont-mount-samsung-evo-850.1971588/post-32926269