I think the thread has drifted away from the specific implications of Covid-19, which are that there is simply no political "bandwidth" to conclude a complex trade negotiation this year while both sides are preoccupied with the pandemic.
The only "oven ready" options available are those that have already been negotiated in the exit treaty, namely WTO terms from the end of 2020 (i.e. no deal), or extension of the transition period on the existing terms. Any sort of temporary "halfway house" deal between these extremes is unrealistic because it would still involve complex and time consuming negotiations. For example, the EU side would never agree to extend transition terms minus the common fishing and agriculture policies, because that would be regarded as "cherry picking". The EU fishing countries want to use market access as a lever to maintain their fishing rights in UK waters.
Covid-19 will make no deal even more chaotic and economically disruptive than it would have been anyway. Neither side will have the time or resources to put in place the systems and border checks needed - customs, immigration, rules of origin, sanitary and phytosanitary checks etc.. Some of the buffer stocks that were built up to protect supply chains against no deal have now been used to mitigate Covid-19 disruption - e.g. medical supplies.
An extension to transition would only need the UK government to amend the domestic legislation, with Covid-19 providing a ready made justification for this policy change. The only real downside would be continued contributions to the EU budget for another year or two - small change compared with the cost of Covid-19. The delay would give the breathing space needed to negotiate a deal that would be much more advantageous to both sides than WTO terms.