Go to the online parameters and extend the visibility of your summon sign, and allow parties with the whole world to have more possibilities with the disadvantages to have some lag. Then stay at a metal level (I had some characters at high level, the online rate is really low). The NG doesn't count for online encounters, only the soul level (and the weapon's level too). In these conditions, on pS4 at SL100, I can summon or be summoned really easily. Aldrich or Filianore Spear covenant is very active too. Im about 350 hours with my more recent character (2019/2020), and i have around 1000 covenant rewards (200 tongues, 100 blue tongues, 50 vertebrae shackles, 50 ears, 100 solar medals, 50 farron's, 300 aldrich's and 100 filianore's rewards). So only based on the rewards, at minimum, I had experienced 3 online playtimes per hour (when I am an invader or summoned). In this count, are not included the many times I summon too, or I get summoned and get rewarded (or not) by an ember… So I estimate that I have actually around 10 online encounters per hour, maybe more. That's very good.