OP:
You're still running Mavericks, the OS that the iMac shipped with in 2014.
You can run something newer than Mavericks (10.9) on a 2014 iMac.
I believe it will run right up to Mojave (10.14).
You didn't tell us WHAT KIND OF DRIVE is inside.
If it's a platter-based hard drive, or a fusion drive, it may be slowing down on you.
You can GREATLY IMPROVE the overall performance by buying a USB3 SSD, plugging it in, installing a later version of the OS, and then making it your boot drive.
This is NOT DIFFICULT and ANYONE can do it.
Won't cost you much $$$, either.
I'd suggest you go online (amazon might be a good start) and check out 2.5" SATA SSDs.
Look at 1tb and 512gb drives.
Don't shop for "the fastest".
I'd suggest Crucial or Sandisk.
Also, get one of these:
SABRENT 2.5 Inch SATA to USB 3.0 Tool Free External Hard Drive Enclosure [Optimized for SSD, Support UASP SATA III] Black (EC-UASP)
tinyurl.com
($9.00 -- you can afford that!)
When you've got the components, put the drive into the enclosure.
Plug it in.
Open disk utility.
Erase/format it to "Mac OS extended with journaling enabled, GUID partition format".
Then come back here, and we'll tell you what to do next.