Changing the oil and oil filter is relatively simple on the 5th Generation Honda Odyssey (years 2018-2023). You do need to lift the car (I recommend driving up onto ramps) in order to access the oil drain plug and the oil filter. It is also slightly challenging filling the engine with oil without making a mess, unless you have a taller funnel or you come up with a more creative way to pour motor oil into the engine fill port.
There are two main ways to reset the Maintenance Minder on the 5th generation Honda Odyssey (2018-2023). If you have an LX trim, you can only reset through the Instrument Panel as you may not have a navigation/infotainment screen on the center dash. If you have an EX trim or higher, you can reset either through the instrument panel or the infotainment screen on the center dash. Either way works and will allow you to reset the maintenance reminders if you’ve completed the maintenance items yourself.