@dp.message_handler(commands=['start'])
async def start(message: types.Message):
await bot.send_message(message.chat.id, 'Ждем: 2сек')
await sleep(1)
await bot.edit_message_text(chat_id=message.chat.id, message_id=message.message_id, text='Ждем: 1сек')
await sleep(1)
await bot.edit_message_text(chat_id=message.chat.id, message_id=message.message_id, text='Готово')
my_new_message = await bot.send_message(message.chat.id, 'Ждем: 2сек')
await sleep(1)
await bot.edit_message_text(chat_id=message.chat.id, message_id=my_new_message.message_id, text='Ждем: 1сек')
...
m = await bot.send_message(message.chat.id, 'Ждем: 2сек')
await m.edit(content = "Ждем: 1сек")