Implement bottom (encode)
APL(Dyalog Unicode), 133 bytes SBCS
{↑,/{⍵=0:'❤️'⋄'',⍨⍬{⍵≥200:(⍺,'')∇⍵-200⋄⍵≥50:(⍺,'')∇⍵-50⋄⍵≥10:(⍺,'✨')∇⍵-10⋄⍵≥5:(⍺,'')∇⍵-5⋄⍵≥1:(⍺,',')∇⍵-1⋄⍺}⍵}¨'UTF-8'⎕ucs⍵}

Try it on APLgolf!
-5 thanks to ovs.