No assistance from airlines to return home after cancellation (due to COVID19), can I get compensated under EC 261?

Last month, Morocco went into lockdown while I was there on holiday. I had tickets with BA. At that time some flights were cancelled but then so-called rescue flights were reinstated.

Airlines such Easyjet and Ryanair offered their customers with an existing ticket seats on these rescue flights (if their flights were cancelled). BA did not. BA did not inform me of flight cancellation. I found out from the news.

When I rang BA, they told me they had no flights left. They offered me flights in April (which were in fact also cancelled) Later on, they introduced extra rescue flights and of course did not offer them to me - why would they when they can sell them for £300 each. After I returned to the UK, I asked them to pay for my new ticket with Ryanair (at £300 single). They offered me refund of my original tickets (£180 return)

The wording of the law is given below. It says i should be able to receive reimbursement or satisfactory rerouting. Of course, I want them to provide re-routing (or cost covering this)

Do I have any legal standing if I am to pursue a claim against them? I was under the impression that airlines were legally obliged to buy you tickets (from rivals) if they cancelled flights from numerous stories i have read before or is this only in the case when they denied you boarding?

Note that delay compensation does not apply here because I think this is an exceptional circumstance, but airlines should offer re-routing or refund in this situation.

https://eur-lex.europa.eu/legal-content/EN/TXT/HTML/?uri=CELEX:32004R0261&from=FR

(12) The trouble and inconvenience to passengers caused by cancellation of flights should also be reduced. This should be achieved by inducing carriers to inform passengers of cancellations before the scheduled time of departure and in addition to offer them reasonable re-routing, so that the passengers can make other arrangements. Air carriers should compensate passengers if they fail to do this, except when the cancellation occurs in extraordinary circumstances which could not have been avoided even if all reasonable measures had been taken.

(13) Passengers whose flights are cancelled should be able either to obtain reimbursement of their tickets or to obtain re-routing under satisfactory conditions, and should be adequately cared for while awaiting a later flight.

EDIT: https://www.caa.co.uk/Passengers/Resolving-travel-problems/Delays-cancellations/Cancellations/Medium-haul-cancellations/ suggests there is a right to re-route. It does not mention any pre-condition for this.