Is your feature request related to a problem? Please describe.

• BIP 156 never got implemented in Bitcoin Core which could improve privacy: https://github.com/bitcoin/bips/blob/master/bip-0156.mediawiki

• Reasons: (TLDR: Denial of Service)
  Dandelion transaction relay (BIP 156) #13947 (comment)

  https://bitcoin.stackexchange.com/a/81504/

• Dandelion++ proposed for Bitcoin: https://arxiv.org/pdf/1805.11060.pdf

• Implemented in Monero: Adding Dandelion++ support to public networks: monero-project/monero#6314

Describe the solution you'd like
Implement Dandelion++ in Bitcoin Core and if it involves any risks, let's test, try to find solutions or workarounds.

Describe alternatives you've considered
Tor

Additional context
Not sure how much is this PR and associated project related to this issue:
#18038

Also there is no option to specify Tor for sendrawtransaction RPC command :
https://bitcoin.stackexchange.com/questions/99442/in-bitcoin-core-how-to-use-tor-for-broadcasting-new-transactions-only