As of January 2021, all of United's 777-200ERs have been reconfigured with Polaris and Premium Plus. This version is known as "Version 1" in United's listing of aircraft (previously version 5).

If you're looking for information about the "High Density" HD) 777-200 configurations used primarily on domestic routes and some trans-Atlantic flights, this thread has it:
Everything You Wanted to Know About Where to Sit on 777-200 HD (28J,102E+,234E-). There is one oddball, N222UA , 32J,124E+, 206E-

The 777-200 Polaris configuration has 50 Polaris business seats in the 1-2-1 configuration used in the 777-300, although with 3 fewer rows. Presumably much of the guidance regarding desirable/less desirable rows from the 777-300 seating thread applies to the 777-200 as well.

Rows 20-22 are the new United Premium Plus seats, in a 2-4-2 configuration. On many flights, UA is not yet selling premium plus as a separate cabin of service, and the seats are sold as E+ seats (though they are much better than standard E+).

Economy is in a 3-4-3 configuration, with 46 Economy+ seats and 156 regular E seats. Economy is using a new Rockwell Aspire seat, which supposedly is more comfortable than current seats (although less space than those used in the past 3-3-3 configuration). While under-seat power outlets are still shared (2 for 3, 3 for 4), the seat back monitors have USB sockets to allow device charging for each individual.



https://www.aerolopa.com/ua-boeing-77e

Guide to Polaris Business Seats:

The center (D/G) seats are generally the same. The odd numbered rows have a larger divider between D and G that can be lowered, so are better for couples that want to interact. The even numbered rows have a smaller divider, so good for solos (or couples who don't really want to talk but to have the chance to). The odd-row seats are located towards the center, with the table towards the aisle. This provides somewhat more privacy than the even-row seats, where the seat is closer to the aisle, with the table towards the center of the plane.

The window (A/L) seats have greater variation. The even-numbered rows (mostly) have one window that requires looking past your table and the partition for other seats. The odd-numbered rows mostly have 2 or 3 windows that are easily accessed, in all cases with the seat right next to the window and the table area towards the aisle side.

* Rows 1, 11, and 15 have 3 windows

* Rows 3 and 5 have two windows

* Row 9 has two windows plus a blank panel for wiring

* Row 7 has a single window plus a blank panel for wiring; The window is the forward part, requiring you to lean forward

* Row 8 has a little more wall space because there's no seat behind it

* Row 12 has no window

Row 1 is adjacent to the galley area at the front of the plane, although the G/L side is closer (the A/D side has a corridor to the lav and cockpit.

9A/L are somewhat protected from the galley, but next to the lavs and across from closets. 9D/G are more fully protected from galley (by those closets) but also have the lav adjacent.

All three rows are similar, except the footrests in Row 20 come from under your own seat rather than the seat in front. All rows have 2 windows, although they are over the wing.