Min/Max From Data with Variables & CONCAT

Hi all, I've spent far to long trying to figure this out & getting nowhere.
Attached sheet with data examples & desired results.

I've been trying formulas along the lines of =IF(COUNTA($L$81:S81)=1,CONCAT($L$81:$S$81),CONCATENATE(MIN(L81:S81),"-",RIGHT(MAX($L$81:$S$81),3))) but this isn't working with the prefix.

Dot points of variable data below,

*Cells will either have a prefix or not, there should never be a scenario where some cells have a prefix & other do not.
*The prefix may not always be the same letter.
*Sometimes there will be 1 value, other times there will be multiple values.
*If there is only 1 value, I just need to duplicate that value
*If there are multiple values, I need the lowest value, in full including prefix as well as the last 3 digits of the highest value as per the examples in the attached sheet.
*The values will not always be in sequential order.

Any help would be appreciated as I've been going around in circles with this for a while now.

Thanks,

Close but not quite, thanks for the reply however.

Your suggestion works with the example file but the issues is a variable prefix character. It will not always be "A", & to put another spin on things, there is a chance it will be more than 1 character but I don't see that being very likely.
I'd like to think that 99% of the time, the prefix character will be the same for each data set i.e. all will start with "A" on this occasion, but the next time they might start with "C". On a very rare occasion, some will start with "A" while another will start with "D" in the same data set for example.

Please try

=LEFT(LOOKUP("z",B2:F2),LEN(LOOKUP("z",B2:F2))-3)&TEXT(AGGREGATE(15,6,--RIGHT(B2:F2,3),1),"000")&REPT(TEXT(AGGREGATE(14,6,--RIGHT(B2:F2,3),1),"-000"),COUNTA(B2:F2)>1)

Still not 100% but good enough to move forward with the project. Thank you.

The reason I saw it's still not right is due to the following hypothetical scenario,
If the values are A00001, B00002 & C00003. The result shows C00001-003

Are you still hoping for help? If not, please mark the thread as solved.

In row 3 - why should DEF change to A? What's the logic there?

What would you want to see returned for your new hypothetical situation?

Finally, does this need to work on Excel 2013, or will it be used exclusively in a 365 environment?

*If there is only 1 value, I just need to duplicate that value

This rule is broken twice in your sample workbook!