New to this thread and just got done with doing my own first oil change and service. Great information here on locations of grease fittings and grease to use. 6 of the 9 fittings are not bad to get to. The remaining 3 took me much more time than I wish to spend on a quick grease service.
Couple things I changed on my 2020 GMC 2500HD to help:
To eliminate the need to come from the top of the pitman and idler arm at the center link, I changed the straight fittings to 90deg. Pointed the grease fittings towards the outside of the truck and now both have very easy access. Standard 1/4-28 taper thread grease fittings. No clearance issues while turning.
(1) top of pitman arm at the center link side of the arm
(1) top of idler arm at the center link side of the arm
To eliminate the need to remove the skid plate or struggling to fit arms in places they don't go, I installed a hose kit from Moog. Part number K6714, purchased off Amazon for $16.28. Grease fitting end mounts to one of the sway bar mounting bolts. Clean looking install.
(1) top of idler arm pivot bracket