CustomMarkdown + quote

class CustomMarkdown:
    @staticmethod
    def parse(text):
        text, entities = markdown.parse(text)
        for i, e in enumerate(entities):
            if isinstance(e, types.MessageEntityTextUrl):
                if e.url == 'quote':
                    entities[i] = types.MessageEntityBlockquote(e.offset, e.length)
                elif e.url.startswith('emoji/'):
                    entities[i] = types.MessageEntityCustomEmoji(e.offset, e.length, int(e.url.split('/')[1]))
        return text, entities

    @staticmethod
    def unparse(text, entities):
        for i, e in enumerate(entities or []):
            if isinstance(e, types.MessageEntityCustomEmoji):
                entities[i] = types.MessageEntityTextUrl(e.offset, e.length, f'emoji/{e.document_id}')
            if isinstance(e, types.MessageEntityBlockquote):
                entities[i] = types.MessageEntityTextUrl(e.offset, e.length, 'quote')
        return markdown.unparse(text, entities)