Opening a weak 2♦ is usually ignored by opponents. Then last year, I started playing a variation of the Mexican 2♦ convention (original by George Rosenkranz). I am not sure of the origin of the variation but with contributions by several KC bridge players, it was modified as follows.
Open 2♦ with 18-19 HCP, even distribution and no 5-card major. Partner controls the auction. This is particularly useful in right siding the contract so the stronger hand is concealed most of the time.
Pass to play in 5+ Diamond suit
2♥ to transfer to 5+ card Spade suit
2♠ to transfer to 2NT (default response)
2NT to transfer to 6+ Club suit
3♦ to transfer to 5+ Heart suit
4♦/4♥ is a Texas Transfer to 4♥/4♠ (for Minorwood, transfer to 2NT first)
Transfer and pass. With no 5-card major or 6-card minor, bid 2♠ to transfer to 2NT then pass.
7+ HCP (Game values)
With 5-5 in the majors, bid 3♣ then Opener can place the contract.
With one 5-card major, transfer to it then bid 3NT. (Responder may play the hand.)
With no 4+ card Major and no 6+card Minor bid 2♠ to transfer to 2NT, then bid 3NT.
Otherwise bid 2♠ to transfer to 2NT then bid:
3NT with no 4-card major or 6-card minor.
3♣ with one 4-card major. With a 4-card major, Opener bids 3♦ and Responder bids the opposite major of the one they hold. Then Opener can place the contract. Similar to Puppet Stayman.
3♦ with two 4-card majors then Opener can place the contract.
3♥ with 5 hearts and 4 spades then Opener can place the contract.
3♠ with 4 hearts and 5 spades then Opener can place the contract.
After opener has set a preferred suit or no-trump, Responder may pass or initiate slam sequences.
There are many variations of Mexican 2♦ but this one works extremely well for me. With interference by Opponents either use Stolen bid or Lebensohl over 1NT responses.