Car takes a few seconds to begin to start

I will preface it is an older car(2002 Toyota RAV4, 8th digit of VIN is 7) but it’s been running pretty much fine ever since I had the engine changed in it(it’s the same as the factory engine, I’m not sure wha

These last few days it’s taken it a second or two longer for the engine to crank but then it starts up with no further problems.

This morning though, I had to hold the key for a solid 5 or so seconds before it would even begin to crank, but once it did, it started up just fine. I’m worried it won’t start when it’s time to go home from work.

I’m at a complete loss when it comes to mechanical stuff so I’m hoping someone here knows what to do, sorry if this is a stupid question