In most cases with 4-5% dispute ratio you do not need a high-risk payment processor. Most of them consider normal to have up to 5% chargebacks.
You should clarify what you mean by dispute ratio because this might be treated differently depending on situations. Are those refunds that you make or chargebacks issued directly to the bank?
I do not know what might be the problem with Stripe. I am using them without any problems. With PayPal we all know that you can get limited or the funds to be hold without any particular reason.
The high-risk payment processors are usually used for a certain type of products that are almost or not everywhere legal. For example v*gra, p*nis enlargement pills, casinos and stuff like this.
They have huge commissions and many of them require to have a bigger threshold with them. For example once they offered me 12% commission for every transaction + holding at least $5,000 with this particular provider.
So, if your store is for general and not banned in any circumstances products, I would suggest you to learn from your mistakes with Stripe and go for a regular payment provider.
The best option is to go with a provider which offers you a bank account with them. For example Paysera. The review process is simple, the commission is only 0.8% per transaction, although they hold 5% from your funds for 3 months. Keep in mind that if you're a dropshipper you can forget about them, although they have written in their terms that dropshippers are welcome
Another option is to use a gateway. Most of them have contracts with different banks and in most cases they will approve you if you provide them with a history from Stripe. The problem is that you need to be approved by the bank of the gateway which sometimes might take months. Example of such a gateway is Gate2Payments.
Based on my experience, you should not rely on only one service. Check their terms and if they fits your business model, apply for as many as you can and eventually you will be approved somewhere. The verification with Stripe is quite easy compared to other solutions.