Problems with inputting into serial monitor
You have hit a bug in the implementation of parseFloat().
This function reads the number you send as an integer, ignoring
the decimal point, and stores it in a long. It then multiplies it by a
scaling factor (a power of 0.1) in order to get the correct value. The
problem is, if you provide too many significant digits, the integer
overflows, and you get garbage. For example &quot;44.64978683&quot; is interpreted
as
(long) 4464978683 * 0.00000001

but (long) 4464978683 overflows and rolls over to 170011387, hence the
result you get.
Simple workaround: do not provide so many significant digits. They are
irrelevant anyway given the resolution of a float.
Edit: I did not find any bug report for this issue, so I submitted my own to the Arduino dev team.
Update: Per request of a maintainer, I submitted a pull
request with a failing unit test revealing this bug. We then worked
on a fix, which has now been merged to master. It should be published on
the next release of ArduinoCore-API.
Note, however, that the AVR core does not yet use the common API
repository. In the meantime, it may be worth submitting a pull request
to ArduinoCore-avr that cherry-picks the fix from ArduinoCore-API.