I dont come from Britain since I'm a belgian citizen but i think it would be intersting if i give my point of view exterior on the brexit situation.
I think it would be better that the Brexit happens normally. Not for the EU but for Britain itself. No matter what type of accords it is or even if you dont get one, you have to leave.
I think a second referendum, without an exit first, would be terrible for the politic situation inside britain, The population stays divised on the subject even today, i've seen a poll about a second referendum on the Twitter europe elect page (i dont have access here but you can easily find it in scrolling), it would be 55% Remain / 45% Leave. I dont feel as I read above that it was just a punish vote against politicians, a lot of citizens strongly think today that it was still good choice.
If a new vote makes Remain in the head of the votes, the middle of the population will feel the democratie is broken. A situation like this could make something that i think you dont want to know. It's the case of France or in the Netherlands where the referendum of 2005 had been broken, these two countries have been still eurosceptists since. Especially France which could, even with a weaker economy, leads EU over Germany in the futur years with best natality of the continent and a nuclear part in the energy very advanced which means they will suffer less of a violent ecology transition. However, the lack of confidence in the politicians have done drastic changes in the country. The two mains political parties since the end of WW2 (centre-left and centre-right) have both almost totally disappeared in only five years to the benefict of three parties, far-right (eurosceptic), center (europhile) and far-left (eurosceptic). The yellow vests have also recently destabilised Macron in pointing notably the lack of democracy and the problems with the EU and the liberalism. This situation isn't specific to France, you know what happened in Italy, which is also an eurosceptic country.
If a brexit happens, you could in twenty five years start a new vote to come back in EU or move still further away if you want. It is still possible. On the other hand, I'm concerned that the Brexit would be a political poison for the next fifty years if a new referendum decides you dont leave. At every elections, the situation will be unsafe with the risk of a new brexit but with a leader far less mainstream. And i'm not sure come back will make the situation economic far better in these conditions, do you prefer invest in a country where you know it isn't in the EU or in a country where you dont know what it will do in the 5, 10 or 15 next years ? Furthermore, you cannot have back the situation such as it was before the Brexit. The only problem isn't only you will be humiliated or dont credible, the problem is also that you have done winners with this vote. Does France have an interest to see you come back ? Spain ? Italy ? Poland ? Does EU really support you ? Big doubts.
Also, but it's a less "important" point, dont think the economy situation is only due to Brexit. Yeah, it has the part of responsability obviously but the decrease of the growth (due to ecology) is a factor which hits all the europe.
To end this, I think the brexit is an unhealthy problem for the political situation of United Kingdom. I feel it imprisons all other discussions you can have because it has link between everything. In matter of education, ecology, equality or technology, i think you have big debates to discuss and it's really too bad you cannot advance with this problem of remain or leave. I understand your issues because I would myself have voted Remain if I lived in United Kingdom but I think it would be better for you if you accomplished the brexit until the end. For your people of course but also to try to have a new political area in the history of Britain, even if it is to come back in 25 years if EU still exists.
Thank you for reading ~