During weekdays, after “rush hour”, it’s not too bad. Rush hour has changed a lot, busiest times are now before 0730. As others have said, it’s probably about 95% mask wearing at the moment. I’ve seen a few times Travel Safe Officers at various points checking mask usage and carrying disposable ones to give to those that don’t have any.
Trains from Crystal Palace will always be quieter than trains from West Croydon. People going to Canada Water or Shoreditch usually bunch up in the first couple carriages. However, people getting on at Crystal Palace and Sydenham usually stay around the rear, so at the moment (due to Canada Water’s one way system), usually able to get seats in middle coaches.
Forest Hill, most get on around first 3 coaches, late comers running for the train go in the fourth.
Honor Oak, mostly last 3.
Brockley first 2.
New Cross Gate mostly last 3 coaches.
Surrey Quays currently 1, 2 or 3.
Canada Water it empties out a lot. If you couldn’t get a seat before, you will get one now no problem.
Rotherhithe, few leave from front couple of coaches.
Wapping, pretty much a few from last coach alight.
Shadwell, mostly last coach, but generally quite spread out.
Whitechapel, usually last couple of coaches people leave from, but again, sometimes spread out.
Shoreditch, mostly first and second people will leave from.
If you haven’t got a seat by now it’d be surprising
Going in other direction, it’s pretty everyone getting on first two coaches at Highbury and Canonbury. Dalston quite a lot get off from all coaches but a few get on in rear but move forward. Haggerston & Hoxton, usually first 2. Shoreditch a lot get off, and mostly front few coaches get most people. Whitechapel a lot leave, a fair amount will get on first coach, but will leave at Shadwell. First 2 at Wapping will see people get on, Rotherhithe is more coach 4, Canada Water is mostly coach 3 (closest to stairs at NXG) and first door of coach 1 (closest to stairs at Surrey Quays). At Surrey Quays, most people get off first and second coach. At New Cross Gate, a few using lift will leave first coach, and most will depart from third. Brockley, mostly first 2 coaches, Honor Oak is first. Forest Hill most leave from rear coach. Sydenham is mostly third. Crystal Palace and Croydon trains have it busier in front coach anyway,
There were a couple of days last week with suspensions beyond NXG, one with no service on LO until approx 0930 so was probably that day.