Replacing 15yr Carrier Infinity / How to decipher


I have one 15 yr old Carrier Infinity that handles the ground floor and it still pumps air to the bonus room above the garage where there has been a Mitsubishi Mini Split for about 12 years. There were two Infinity systems installed about the same time nearly 15 yrs ago. When we had a $**** (quoted) repair on one a couple of years ago I replaced that with a Daikin. Everything is working fine. I look at energy usage, a lot of variables have changed, thermostat set temps not the same, new windows installed after the Daikin etc, but as far as I can tell the Daikin has helped. Plus it is whisper quiet (the outside unit). The remaining Infinity is reciprocating comp. and NOISY. So with the new tax reduction act and a desire to sit near the units on our patio and enjoy the outdoors with quiet stimulates a replacement.
My question: (1) How do I evaluate the comments of two different techs. The one who did the annual maint. in Dec 21 said “Don’t you ever replace the Infinity till it breaks, it is running great”. He left the company thereafter. The guy who did the last maint. service in April-May 22 said that the compressor “was coming on slow”. I think I’m qualified to get a more technical answer but pressing him for a more accurate answer was of no avail.
(2) Second question: When I replace the Infinity I’m wondering if I should get a larger unit to handle the bonus room upstairs. Before I got the Mini Split for the upstairs my downstairs unit did just that but it never handled the load properly and we were advised to get the Mini Split to have an independent source. Also I feel that the techs do not understand Mini Splits (well the Daikin is a multi stage). The previous company I had (I fired) neglected to drain/check the condensate line and I had a leak in the bonus room that runed the laminate floor (and a subwoofer). When I asked the first maintenance guy they sent he said “They just do that (leak)”. Then they sent a NATE certified tech and he said “Why didn’t you tell them to check the drain line” !!!!! The guy who came this April (current company), when I said the Split was not cooling properly, put the thermostat in dry mode, which does not allow you to set the temperature.
I pay for twice a year maintenance and I like getting feedback on what was done. The previous company used to give me all the readings they took, I got rid of them because of how they handled the mini split condensate leak, plus they seemed to be more interested in add on services. The current company just tells me “everything looks good”.

Please do not add pricing to your posts. It is not allowed by forum rules.