Bitcoin Segwit was released in the summer of 2017 to reduce the blocksize congestion. Why is it still congested? Segwit was released in the summer of 2017 to resolve the network congestion. Why is the network still congested? Didn't it enable 1MB blocks to become 2MB blocks? Or do you have to wait for wallet providers to make use of the segwit portion of the software?
SegWit cannot, and was never designed to "resolve network congestion". It:


fixes the third-party malleability issue that Bitcoin has had since its creation, vastly simplifying many multi-transaction smart contract constructions (like Lightning). 
fixes the O(N2) signature hashing problem.
adds amount commitments to signature hashing, simplifying design of hardware signing modules ("hardware wallets")
adds script versioning, making it significantly easier to add new features later as a soft fork
introduces a scripthash mode with 128-bit security (P2SH only has 80-bit security against certain attacks)
introduces a discount factor 4 for signatures w.r.t. block size accounting, partially rectifying the issue that creating an output is far cheaper than spending one.


All of the points above are improvements to Bitcoin in the long term w.r.t. scalability and security. In addition, the last point also indirectly provides a modest capacity increase - allowing a bit more throughput for those who choose to use new-style transactions. This is justified by the fact that simultaneously some of the worst-case costs to the network are removed (the O(N2) sighashing), and technological improvements for block relay (see BIP152). It is by no means a blanket "let's double capacity" - more an improvement in the accuracy in counting the cost of transactions, which happens to make things cheaper for the most common ones.

Regarding network congestion, that's just a fact of life if the network is operating sanely. It's both necessary for the system's survival (as the miner subsidy diminishes, fees more and more directly define the incentive for miners to secure the network), and a logical result of any restriction in capacity - whether that is 1MB or 2MB or 100MB blocks. If capacity in blocks isn't being used, the price of block space will drop, and new use cases will develop. For example, if the available space isn't being used for extended periods of time, I expect the feerate to go so low that people will start to try to put their backups in those blocks - burdening the whole world. Essentially, what you call network congestion is just a sign of a functioning fee market: if you don't limit the price, the demand will become infinite.

Disclaimer: I designed a significant part of SegWit.