How do I enable Extended Tracking in the inReach MINI 2?

Comparing the owner's manuals, it seems extended tracking does not exist in the MINI 2.

Relevant page for inReach MINI: https://www8.garmin.com/manuals/webhelp/inreachmini/EN-US/GUID-089C5143-55A5-4764-95ED-2EA71DBC21D7.html

Relevant page for inReach MINI 2: https://www8.garmin.com/manuals/webhelp/GUID-802DEF62-EBB2-463C-8C51-C58FB29F89E3/EN-US/GUID-089C5143-55A5-4764-95ED-2EA71DBC21D7.html

Is there a way to get battery life for inReach MINI 2 comparable with the inReach MINI extended tracking mode?

Garmin has decreed that this should be harder than it needs to be on the M2. Or that the M2 has such good battery life that you don't need it. ;)

Best you can do is to set various things manually as follows. The point here is to minimize GPS radio use, iR modem use, display power sucking, BT radio use, ANT+ radio use. You can use whichever of these features you need so long as you understand that doing so will increase battery drain.

Tracking interval as high as you can tolerate. The 10 minute default is good.

Activity recording set to standard, not high detail. You can't shut it off entirely.

Display brightness as low as you can tolerate. Preferably zero.

Display timeout as low as you can tolerate.

Bluetooth off. Either do not pair with a phone, or turn off the phone connection.

ANT+ off. Either do not pair with a remote control device, or turn it off.

For safety reasons, I don't recommend NOT tracking. If you become disabled to the point where you cannot send an SOS, the track gives SAR a starting point when somebody eventually reports you missing. 

Since you are tracking, be sure to carry device in a manner which gives it a good sky view when available. The ideal location for an M1 or M2 is on your pack strap, high on your shoulder. DO NOT put the device in your pack, even on top. Pocket or belt hook is less than optimal because your body blocks too much of the sky. Point here is to minimize iR communication retries (on track send, message send, or automatic message check), which suck battery.

NEVER, EVER depend on the manufacturers claimed battery life. It might be a valid claim. Or it might not. It's not worth your life to find out. The typical solution here is to carry a backup charging source - a power bank or a solar charger. Do not depend on the M2 battery lasting 2 weeks.

If you use tracking but turn off send intervals willi incurr any additional costs to my subscription plan?