England doesn't have an ODI tournament. ODIs are only played between international teams.
Irish and Dutch players have vanished from the English counties in recent years due to Brexit. Kolpak doesn't apply in UK anymore so if counties want to sign Irish or Dutch players they have to sign them on overseas deals. No county wants to waste precious overseas spots on average Irish or Dutch players. The good players from these countries (the likes of Josh Little) are headhunted by franchises in all the big leagues so they get naturally drawn towards T20s.
The one day cup in England is extremely poor nowadays. The Blast is the main limited overs county competition. The one day cup is played when all the best players are with their franchises at The Hundred. England's ODI selections are more or less just based on T20/Hundred performances.
Growing up ODI was the format I enjoyed the most. It wasn't slow and drawn out like tests and it wasn't 'attempt to smash every ball out of the park without showing any technical ability' like T20Is. Those days are gone now. Tests are being played at higher run rates. T20 isn't a meme format anymore. ODI is unfortunately the odd one out. Now it's just an extended T20 with worse crowds. We've seen in the Asia Cup recently and the opening week of the WC that a lot of matches start with non-existing crowds, only for a half-decent turnout by the time the second innings starts. They're just showing up for 3-4 hours which is the length of a T20 game. People simply don't have the time or appetite to watch cricket for 8 hours.
Calls for bilateral ODI series to be scrapped are getting louder and louder due to time constraints and tighter schedules. Soon we'll only have ODIs at World Cups. ODI is a dying format whether you and I like it or not.
And T20 is your ticket to that.
You're talking about WI, Zim and Ireland and wanting to give them more ODI exposure. Giving them a free pass to the World Cup will achieve feck all. Ultimately their List A structure is either non-existent or simply just not good enough. A World Cup spot won't change any of that.
ODIs are only played between selected few nations with ODI status. It's a format for the elite. T20Is can be played by any ICC member. This is a deliberate ploy. ICC wants T20 to be the main domestic comp everywhere. And rightly so, that's the only way the game can be expanded and they're well aware of that.
If you guys actually are serious about lower ranked teams getting exposure you simply have to acknowledge that T20 is the only format for that. And I'm not talking about the likes of WI, Zim and Ire (these are 3 of the 12 full members in cricket) but rest of the countries who make up the top 50
here. All cricketers from these countries are amateurs. They spend their time working/studying. They will never develop skills to compete against the big boys over 50 overs. T20 is however a perfect format for it. The shorter the format the smaller the difference between teams. Funding, sponsors, time constraint wise etc. T20 is the only format that makes sense for lower ranked countries.