Visiting UK while going through spouse visa application

I am a Brazilian national living in the UK on a Tier 2 visa. I recently got married, and my wife, also Brazilian, is applying for a UK Tier 2 dependant visa.
She has already completed the online application and now the next step is to attend an appointment at the Visa Application Centre in Brazil to submit her biometrics and turn in her passport.
This appointment is in 4 weeks.
We booked a flight for her to fly from Brazil to the UK to visit me this week, returning to Brazil a couple days before her visa appointment.
Question: is she allowed to enter the UK as a visitor at this stage of the application process? Will she be denied entry?
Additionally, are there restrictions around Brazilians visiting the UK due to COVID-19, other than the 14 days quarantine?
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Can I visit the UK while my spouse visa is being processed?
If you are going through the UKVCAS process, you should not plan to travel outside of the country until you have received your decision. If you have travelled and your application has been withdrawn, then you will have no legal right to re-enter the UK and make another application.Can I stay in UK while waiting for my spouse visa?
You can stay in the UK until you've been given a decision, as long as you applied before your last visa expired.Can you visit the UK while applying for a visa?
You must apply for a Standard Visitor visa online before you travel to the UK. A Standard Visitor visa costs \xa3100 for up to 6 months. The earliest you can apply is 3 months before you travel. If you visit the UK regularly, you can choose to apply for a long-term Standard Visitor visa instead.Can you apply for a tourist visa while waiting for a partner visa?
It's possible to visit your spouse in the United States while your marriage-based green card application is pending. In order to do so, you would need to apply for a tourist visa. But before pursuing this option, it's important to understand the challenges and risks involved.MARRIAGE VISIT VISA IN THE UK | How to bring your partner in the UK? | Life in the UK
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