Yes, there are solutions for the partial payment and multi-currency problem in Odoo v13. Here are some options:

Use the Multi-currency and Multi-payment add-on: This add-on allows you to receive partial payments in different currencies. It supports multiple payment methods and currencies, and automatically generates exchange differences entries.

Manually create exchange difference entries: If you're not using the Multi-currency and Multi-payment add-on, you can manually create exchange difference entries when a payment is reconciled with an invoice. This requires manual intervention and can be time-consuming.

Use a third-party payment gateway: Some payment gateways support multi-currency payments and automatic exchange rate conversion. This can simplify the reconciliation process and help ensure accurate exchange rate calculations.

Upgrade to a newer version of Odoo: Odoo v14 and later versions have improved support for multi-currency payments and exchange rate calculations. Upgrading to a newer version may help solve some of the issues you're experiencing.

Ultimately, the solution that's best for you will depend on your specific needs and the complexity of your payment processing. It's important to carefully evaluate your options and choose a solution that meets your requirements.ame steps as above to configure your outgoing email templates and send invoices by email.