It is really hard to show or I know nothing about Odoo.

Add to your model something like this

@api.one
def _compute_amount_each_currency(self):
    sums=dict([(l.currency_id.name,0) for l in self.expense_ticket_line_ids])
    for line in self.expense_ticket_line_ids:
        sums[line.currency_id.name]+=line.amount_currency
    self.amount_each_currency=json.dumps(sums)
amount_each_currency = fields.Text(compute='_compute_amount_each_currency')

So we have got the field with the sums for each currency. This is the easiest part.

And now show time!

I'm still upset that <templetes> is available only in a kanban view. Am I right?

So in a form view I see only two ways. The first is to add another text field with appropriate text like 'Totals EUR: xxx, CYN: xxx, USD: xxx' in one line and add this field to the view. Baldly but I can't find another way.

A report is more flexible and here we can make it nice looking.  Create a model with the render_html function

class ReportSometing(models.AbstractModel):
    @api.one
    def render_html(self, data=None):
    [...]
    if objects[0]:
        sums=json.loads(objects[0].amount_each_currency)
        sums=[[key,value] for key,value in sums.items()]
    else:
        sums=[]
    docargs = {
        'sums': sums,
    }
    [...]

and convert the field with each currency totals into the list of lists of a currency name and its amount.

Insert into the report something like the following and get the profit.

<t t-foreach="sums" t-as="i">
     <p><t t-esc="i[0]"/><t t-esc="i[1]"/></p>
</t>

Season with any decoration.

Well.. the second way is to create a separate table with sums for each currency like the class AccountInvoiceLine(models.Model). The code is in brief. I did not test the whole idea.

class ExpenseTicket(models.Model):
    expense_ticket_currency_ids = fields.One2many('expense.ticket.currency', 'expenseticket_id')

class ExpenseTicketCurrency(models.Model):
    _name = "expense.ticket.currency"
    expenseticket_id = fields.Many2one('expense.ticket', string='', ondelete='cascade', index=True)
    currency_id = fields.Many2one('res.currency',string='Currency')
    amount_currency=fields.Monetary(string='Amount', currency_field='currency_id')

In a view we can use 'tree'

<field name="expense_ticket_currency_ids">
 <tree string="">
 <field name="currency_id"/>
 <field name="amount_currency"/>
 </tree>
</field>

The last part is to write functions to store data into ExpenseTicketCurrency.