With the new power houses pokemon are the other pokemons in pve still useful to power up?

I mean for people who do solo raids or maybe also duo.. in what cases investing in 2nd tier pokemon is still useful?
For example is there any point in using them if you have a lvl 50 Ray/Necrozma/Groudon now with fusion kyruem etc .. is it better to use a solo rayquaza and relobby or use rayquaza/palkia SR/ shadow salamance etc?
If i have a double lvl 50 dawn mane necrozma is it better to use only them and relobby or also use like a lvl 50 yveltal?
Is there any info at what point is better relobby than using another pokemon?
For example if u have only 1 lvl 50 necrozma its better to also use yveltal etc than relobbyng but if u have 2 lvl 50 Necrozma than relobby is better?