I apologize about the battery comment. While thinking I sometimes lose track mentally of what has been done.
The “slow to start” could be interpreted in different ways and lead to many different conclusions so there would have to be clarity on that.
Slow to start could mean the engine is cranking over slowly by the starter motor, engine turns over a number of times in a normal speed before actually starting, engine starting and running rough for a short period before smoothing out, and so on.