iMac(2017) i5 intel Dual Core slow to open programs.

Apple released three iMacs in 2017.

Two of them had Retina screens and quad-core CPUs. It sounds like yours is the 21.5" model which does not have a Retina screen, and which has a dual-core CPU, with a lower clock frequency than the CPUs in other 2017 iMacs.

I am guessing that your machine has either a slow 1 TB 5400 rpm hard drive, or a slow 1 TB Fusion Drive that pairs that same hard drive with a very small amount of SSD storage. A slow drive might be even more of an issue than a slow CPU.

Servant of Cats is is spot on. That is indeed the crippled "educational/institutional" model aimed at bulk buyers with minimal computer needs. For a US$200 savings, buyers got considerably less performance.

These are benchmark scores from the MacTracker database (free in the Mac App Store) for the "edu-iMac" and and the regular consumer version that year that had quad-core i5s:

Even then, history says the slow and under-spec mech hard drive Apple used in entry-level iMac is more likely the culprit here. That fits "slow app launch:" symptoms.

Fortunately, the EtreCheck report will let us diagnose and make recommendations based on data, not history.

Install EtreCheck and post the report. Allow Full Disk Access.

https://etrecheck.com/

Use the Additional Text icon to paste in the report.