It is as simple as if bitcoin transaction has been confirmed, it can not longer be reversed even as non replace-by-fee transaction can not be reversed at all even if not confirmed, the chance it will be reserved is almost impossible.

Bitcoin high transaction fee? No. Maybe you are using exchanges which have higher withdrawal fee. Bitcoin network transaction fee depends how congested the mempool is, but mempool has been less congested more than congested.

The person that sent bitcoin to me day before yesterday use 1 sat/vbyte, I sent bitcoin someone yesterday with 1 sato/vbyte. I checked the mempool now, it is at 4 sat/vbyte but 1 sat/vbyte still got confirmed faster recently.

Bitcoin at ₦38400

1 sat/vbyte is around $0.05 as fee
4 sat/vbyte is around $0.2 as fee.

There are sometimes the mempool can be congested, the last time I remember was the early bull run of 2020, the mempool was congested in around February to early April 2020, the mempool later decongested. After was the China ban on bitcoin mining, but the mempool was not that congested and there is difficulty adjustment every 2016 blocks, that is around every 2 weeks.

Use a reputed wallet hay have good fee estimation, or you can use https://mempool.space to know the best fee rate, some what can over estimate and make you pay more than usual.

That is true, comparing segwit to legacy, for 1 input and 2 output, there is 42% fee reduction whole sending from Segwit address to segwit address compared to while sending from legacy address to legacy address.

@Raymond Gary
Segwit addresses starts from bc1