2003 Toyota Corolla Transmission Problem

I have 2003 Toyota Corolla 2003 (NZE) 1NZ-FE.
When my car is wormed up number 1, 2 and probably 3. As soon as it shifts from first to second there is a pause, and the gear changes, if I was to mash down aggressively it changes good, the problem is stop and Go.
(1) Oil level good no leaks.
(2) From N to P and R the gear selects on time, overdrive good.
(3) The color of oil is light red/ brownish

Another problem recently when driving slowly
on second gear, to stop I let my foot of the gas, and I notices my RMP would drop and go back up, normally the car would slow down evenly, now it feels like a break and the release. But at high speeds slowing down the car reduces speed normal.

Please Help!